fix: don't skip tab updates while dragging

This causes an endless render loop because the hover status
ping pongs. This was probably originally added to avoid dangling
widget pointers. We handle that correctly now elsewhere with
is_live_widget_ptr.

src/tui/Button.zig

@@ -123,7 +123,7 @@ fn State(ctx_type: type) type {
                     input.mouse.BUTTON1 => {
                         self.active = true;
                         self.drag_anchor = self.to_rel_cursor(x, y);
-                        tui.need_render();
+                        tui.need_render(@src());
                     },
                     input.mouse.BUTTON4, input.mouse.BUTTON5 => {
                         self.call_click_handler(btn_enum, self.to_rel_cursor(x, y));
@@ -136,7 +136,7 @@ fn State(ctx_type: type) type {
                 self.drag_anchor = null;
                 self.drag_pos = null;
                 self.call_click_handler(@enumFromInt(btn), self.to_rel_cursor(x, y));
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             } else if (try m.match(.{ "D", input.event.press, tp.extract(&btn), tp.any, tp.extract(&x), tp.extract(&y), tp.any, tp.any })) {
                 self.drag_pos = .{ .x = x, .y = y };
@@ -153,11 +153,11 @@ fn State(ctx_type: type) type {
                 self.drag_anchor = null;
                 self.drag_pos = null;
                 self.call_click_handler(@enumFromInt(btn), self.to_rel_cursor(x, y));
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             } else if (try m.match(.{ "H", tp.extract(&self.hover) })) {
                 tui.rdr().request_mouse_cursor_pointer(self.hover);
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             }
             self.drag_anchor = null;

src/tui/InputBox.zig

@@ -132,21 +132,21 @@ pub fn State(ctx_type: type) type {
         pub fn receive(self: *Self, _: tp.pid_ref, m: tp.message) error{Exit}!bool {
             if (try m.match(.{ "B", input.event.press, @intFromEnum(input.mouse.BUTTON1), tp.any, tp.any, tp.any, tp.any, tp.any })) {
                 self.active = true;
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             } else if (try m.match(.{ "B", input.event.release, @intFromEnum(input.mouse.BUTTON1), tp.any, tp.any, tp.any, tp.any, tp.any })) {
                 self.opts.on_click(self.opts.ctx, self);
                 self.active = false;
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             } else if (try m.match(.{ "D", input.event.release, @intFromEnum(input.mouse.BUTTON1), tp.any, tp.any, tp.any, tp.any, tp.any })) {
                 self.opts.on_click(self.opts.ctx, self);
                 self.active = false;
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             } else if (try m.match(.{ "H", tp.extract(&self.hover) })) {
                 tui.rdr().request_mouse_cursor_pointer(self.hover);
-                tui.need_render();
+                tui.need_render(@src());
                 return true;
             }
             return false;

src/tui/Widget.zig

@@ -55,7 +55,7 @@ pub const VTable = struct {
     walk: *const fn (ctx: *anyopaque, walk_ctx: *anyopaque, f: WalkFn, self_widget: *Self) bool,
     focus: *const fn (ctx: *anyopaque) void,
     unfocus: *const fn (ctx: *anyopaque) void,
-    hover: *const fn (ctx: *anyopaque) bool,
+    hover: *const fn (ctx: *const anyopaque) bool,
     type_name: []const u8,
 };
 
@@ -154,8 +154,8 @@ pub fn to(pimpl: anytype) Self {
                 }
             }.unfocus,
             .hover = struct {
-                pub fn hover(ctx: *anyopaque) bool {
+                pub fn hover(ctx: *const anyopaque) bool {
-                    return if (comptime @hasField(child, "hover")) @as(*child, @ptrCast(@alignCast(ctx))).hover else false;
+                    return if (comptime @hasField(child, "hover")) @as(*const child, @ptrCast(@alignCast(ctx))).hover else false;
                 }
             }.hover,
         },
@@ -170,7 +170,7 @@ pub fn dynamic_cast(self: Self, comptime T: type) ?*T {
 }
 
 pub fn need_render() void {
-    tui.need_render();
+    tui.need_render(@src());
 }
 
 pub fn need_reflow() void {
@@ -203,7 +203,10 @@ pub fn update(self: Self) void {
 }
 
 pub fn render(self: Self, theme: *const Theme) bool {
-    return self.vtable.render(self.ptr, theme);
+    const more = self.vtable.render(self.ptr, theme);
+    if (more)
+        tp.trace(tp.channel.widget, .{ "continue_by", self.vtable.type_name });
+    return more;
 }
 
 pub fn resize(self: Self, pos: Box) void {
@@ -242,7 +245,7 @@ pub fn unfocus(self: *Self) void {
     self.vtable.unfocus(self.ptr);
 }
 
-pub fn hover(self: *Self) bool {
+pub fn hover(self: *const Self) bool {
     return self.vtable.hover(self.ptr);
 }
 
@@ -313,7 +316,7 @@ pub fn empty(allocator: Allocator, parent: Plane, layout_: Layout) !Self {
                 pub fn unfocus(_: *anyopaque) void {}
             }.unfocus,
             .hover = struct {
-                pub fn hover(_: *anyopaque) bool {
+                pub fn hover(_: *const anyopaque) bool {
                     return false;
                 }
             }.hover,

src/tui/editor.zig

@@ -6934,7 +6934,7 @@ pub const EditorWidget = struct {
                     return;
                 } else {
                     self.editor.cancel_all_matches();
-                    tui.need_render();
+                    tui.need_render(@src());
                 }
             },
             .none => {},

src/tui/home.zig

@@ -209,7 +209,7 @@ pub fn receive(_: *Self, _: tp.pid_ref, m: tp.message) error{Exit}!bool {
     var hover: bool = false;
     if (try m.match(.{ "H", tp.extract(&hover) })) {
         tui.rdr().request_mouse_cursor_default(hover);
-        tui.need_render();
+        tui.need_render(@src());
         return true;
     }
     if (try m.match(.{ "B", input.event.press, @intFromEnum(input.mouse.BUTTON1), tp.more }) or
@@ -453,7 +453,7 @@ const cmds = struct {
         const padding = tui.get_widget_style(widget_type).padding;
         self.menu_len = self.menu_count + padding.top + padding.bottom;
         self.menu_w = self.menu_label_max + 2 + padding.left + padding.right;
-        tui.need_render();
+        tui.need_render(@src());
         try tui.save_config();
     }
     pub const home_next_widget_style_meta: Meta = .{};

src/tui/mainview.zig

@@ -605,7 +605,7 @@ const cmds = struct {
             if (view == null)
                 try command.executeName("scroll_view_center", .{});
         }
-        tui.need_render();
+        tui.need_render(@src());
         self.location_update_from_editor();
     }
 
@@ -613,7 +613,7 @@ const cmds = struct {
         tui.reset_drag_context();
         try self.create_editor();
         try command.executeName("open_scratch_buffer", command.fmt(.{ "help", @embedFile("help.md"), "markdown" }));
-        tui.need_render();
+        tui.need_render(@src());
         self.location_update_from_editor();
     }
     pub const open_help_meta: Meta = .{ .description = "Open help" };
@@ -622,7 +622,7 @@ const cmds = struct {
         tui.reset_drag_context();
         try self.create_editor();
         try command.executeName("open_scratch_buffer", command.fmt(.{ "font test", @import("fonts.zig").font_test_text, "text" }));
-        tui.need_render();
+        tui.need_render(@src());
         self.location_update_from_editor();
     }
     pub const open_font_test_text_meta: Meta = .{ .description = "Open font glyph test text" };
@@ -631,7 +631,7 @@ const cmds = struct {
         tui.reset_drag_context();
         try self.create_editor();
         try command.executeName("open_scratch_buffer", command.fmt(.{ "version", root.version_info, "gitcommit" }));
-        tui.need_render();
+        tui.need_render(@src());
         self.location_update_from_editor();
     }
     pub const open_version_info_meta: Meta = .{ .description = "Version" };
@@ -726,7 +726,7 @@ const cmds = struct {
         tui.reset_drag_context();
         try self.create_editor();
         try command.executeName("open_scratch_buffer", .{ .args = args });
-        tui.need_render();
+        tui.need_render(@src());
         self.location_update_from_editor();
     }
     pub const create_scratch_buffer_meta: Meta = .{ .arguments = &.{ .string, .string, .string } };
@@ -807,7 +807,7 @@ const cmds = struct {
                 new_buffer.mark_dirty();
                 new_editor.clamp();
                 new_editor.update_buf(new_buffer.root) catch {};
-                tui.need_render();
+                tui.need_render(@src());
             }
             try command.executeName("save_file", .{});
             try command.executeName("place_next_tab", command.fmt(.{
@@ -836,7 +836,7 @@ const cmds = struct {
         const logger = log.logger("buffer");
         defer logger.deinit();
         logger.print("deleted buffer {s}", .{file_path});
-        tui.need_render();
+        tui.need_render(@src());
     }
     pub const delete_buffer_meta: Meta = .{ .arguments = &.{.string} };
 
@@ -852,13 +852,13 @@ const cmds = struct {
             return;
         }
         _ = self.buffer_manager.close_buffer(buffer);
-        tui.need_render();
+        tui.need_render(@src());
     }
     pub const close_buffer_meta: Meta = .{ .arguments = &.{.string} };
 
     pub fn restore_session(self: *Self, _: Ctx) Result {
         try self.read_restore_info();
-        tui.need_render();
+        tui.need_render(@src());
     }
     pub const restore_session_meta: Meta = .{};
 
@@ -1117,7 +1117,7 @@ const cmds = struct {
         if (self.get_active_editor()) |editor| if (std.mem.eql(u8, file_path, editor.file_path orelse "")) {
             self.symbols_complete = true;
             try tui.open_overlay(@import("mode/overlay/symbol_palette.zig").Type);
-            tui.need_render();
+            tui.need_render(@src());
         };
     }
     pub const add_document_symbol_done_meta: Meta = .{
@@ -1181,7 +1181,7 @@ const cmds = struct {
                     .palette => try tui.open_overlay(@import("mode/overlay/completion_palette.zig").Type),
                     .dropdown => try tui.open_overlay(@import("mode/overlay/completion_dropdown.zig").Type),
                 }
-                tui.need_render();
+                tui.need_render(@src());
             }
         };
     }
@@ -1383,7 +1383,7 @@ const cmds = struct {
         const buffer = self.buffer_manager.buffer_from_ref(buffer_ref) orelse return;
         if (self.get_editor_for_buffer(buffer)) |editor| if (editor.buffer) |eb| if (eb == buffer) {
             editor.smart_buffer_append(command.fmt(.{output})) catch {};
-            tui.need_render();
+            tui.need_render(@src());
             return;
         };
         var cursor: Buffer.Cursor = .{};
@@ -1393,7 +1393,7 @@ const cmds = struct {
         _, _, root_ = try root_.insert_chars(cursor.row, cursor.col, output, self.allocator, metrics);
         buffer.store_undo(&[_]u8{}) catch {};
         buffer.update(root_);
-        tui.need_render();
+        tui.need_render(@src());
     }
     pub const shell_execute_stream_output_meta: Meta = .{ .arguments = &.{ .integer, .string } };
 
@@ -1407,7 +1407,7 @@ const cmds = struct {
             return;
         }
         buffer.mark_clean();
-        tui.need_render();
+        tui.need_render(@src());
     }
     pub const shell_execute_stream_output_complete_meta: Meta = .{ .arguments = &.{ .integer, .string } };
 
@@ -2074,12 +2074,12 @@ pub fn set_info_content(self: *Self, content: []const u8, mode: enum { replace,
         .replace => info.set_content(content) catch |e| return tp.exit_error(e, @errorReturnTrace()),
         .append => info.append_content(content) catch |e| return tp.exit_error(e, @errorReturnTrace()),
     }
-    tui.need_render();
+    tui.need_render(@src());
 }
 
 pub fn cancel_info_content(self: *Self) tp.result {
     _ = self.toggle_panel_view(info_view, .disable) catch |e| return tp.exit_error(e, @errorReturnTrace());
-    tui.need_render();
+    tui.need_render(@src());
 }
 
 pub fn vcs_id_update(self: *Self, m: tp.message) void {

src/tui/mode/mini/file_browser.zig

@@ -179,7 +179,7 @@ pub fn Create(options: type) type {
             } else {
                 log.logger("file_browser").err("receive", tp.unexpected(m));
             }
-            tui.need_render();
+            tui.need_render(@src());
         }
 
         fn add_entry(self: *Self, file_name: []const u8, entry_type: EntryType, file_type: []const u8, icon: []const u8, color: u24) !void {

src/tui/mode/overlay/dropdown.zig

@@ -298,7 +298,7 @@ pub fn Create(options: type) type {
                     self.menu.select_down();
                 const padding = tui.get_widget_style(widget_type).padding;
                 self.do_resize(padding);
-                tui.refresh_hover();
+                tui.refresh_hover(@src());
                 self.selection_updated();
             }
         }
@@ -580,7 +580,7 @@ pub fn Create(options: type) type {
                 tui.set_next_style(widget_type);
                 const padding = tui.get_widget_style(widget_type).padding;
                 self.do_resize(padding);
-                tui.need_render();
+                tui.need_render(@src());
                 try tui.save_config();
             }
             pub const overlay_next_widget_style_meta: Meta = .{};

src/tui/mode/overlay/open_recent.zig

@@ -273,7 +273,7 @@ fn process_project_manager(self: *Self, m: tp.message) MessageFilter.Error!void
             self.menu.select_down();
             self.need_select_first = false;
         }
-        tui.need_render();
+        tui.need_render(@src());
     } else if (try cbor.match(m.buf, .{
         "PRJ",
         "recent",
@@ -291,7 +291,7 @@ fn process_project_manager(self: *Self, m: tp.message) MessageFilter.Error!void
             self.menu.select_down();
             self.need_select_first = false;
         }
-        tui.need_render();
+        tui.need_render(@src());
     } else if (try cbor.match(m.buf, .{ "PRJ", "recent_done", tp.extract(&self.longest), tp.extract(&query), tp.extract(&self.total_files_in_project) })) {
         self.update_count_hint();
         self.query_pending = false;
@@ -492,7 +492,7 @@ const cmds = struct {
     pub fn overlay_next_widget_style(self: *Self, _: Ctx) Result {
         tui.set_next_style(widget_type);
         self.do_resize();
-        tui.need_render();
+        tui.need_render(@src());
         try tui.save_config();
     }
     pub const overlay_next_widget_style_meta: Meta = .{};

src/tui/mode/overlay/palette.zig

@@ -349,7 +349,7 @@ pub fn Create(options: type) type {
                     self.menu.select_down();
                 const padding = tui.get_widget_style(widget_type).padding;
                 self.do_resize(padding);
-                tui.refresh_hover();
+                tui.refresh_hover(@src());
                 self.selection_updated();
             }
         }
@@ -635,7 +635,7 @@ pub fn Create(options: type) type {
                 tui.set_next_style(widget_type);
                 const padding = tui.get_widget_style(widget_type).padding;
                 self.do_resize(padding);
-                tui.need_render();
+                tui.need_render(@src());
                 try tui.save_config();
             }
             pub const overlay_next_widget_style_meta: Meta = .{};

src/tui/mode/overlay/vcs_status.zig

@@ -188,7 +188,7 @@ fn process_project_manager(self: *Self, m: tp.message) MessageFilter.Error!void
             self.menu.select_down();
             self.need_select_first = false;
         }
-        tui.need_render();
+        tui.need_render(@src());
     } else if (try cbor.match(m.buf, .{
         "PRJ",
         "new_or_modified_files",
@@ -207,7 +207,7 @@ fn process_project_manager(self: *Self, m: tp.message) MessageFilter.Error!void
             self.menu.select_down();
             self.need_select_first = false;
         }
-        tui.need_render();
+        tui.need_render(@src());
     } else if (try cbor.match(m.buf, .{ "PRJ", "new_or_modified_files_done", tp.extract(&self.longest), tp.extract(&query) })) {
         self.query_pending = false;
         self.need_reset = true;
@@ -369,7 +369,7 @@ const cmds = struct {
     pub fn overlay_next_widget_style(self: *Self, _: Ctx) Result {
         tui.set_next_style(widget_type);
         self.do_resize();
-        tui.need_render();
+        tui.need_render(@src());
         try tui.save_config();
     }
     pub const overlay_next_widget_style_meta: Meta = .{};

src/tui/status/clock.zig

@@ -95,7 +95,7 @@ pub fn render(self: *Self, theme: *const Widget.Theme) bool {
 
 fn receive_tick(self: *Self, _: tp.pid_ref, m: tp.message) MessageFilter.Error!bool {
     if (try cbor.match(m.buf, .{"CLOCK"})) {
-        tui.need_render();
+        tui.need_render(@src());
         self.update_tick_timer(.ticked);
         return true;
     }

src/tui/status/tabs.zig

@@ -104,6 +104,7 @@ pub const TabBar = struct {
     const TabBarTab = struct {
         buffer_ref: usize,
         widget: Widget,
+        view: ?usize,
     };
 
     fn init(allocator: std.mem.Allocator, parent: Plane, event_handler: ?EventHandler, min_tabs: ?usize) !Self {
@@ -138,9 +139,14 @@ pub const TabBar = struct {
     }
 
     pub fn update(self: *Self) void {
-        self.update_tabs() catch {};
+        const drag_source, const drag_btn = tui.get_drag_source();
+        self.update_tabs(drag_source) catch {};
         self.widget_list_widget.resize(Widget.Box.from(self.plane));
         self.widget_list_widget.update();
+        for (self.widget_list.widgets.items) |*split_widgetstate| if (split_widgetstate.widget.dynamic_cast(WidgetList)) |split|
+            for (split.widgets.items) |*widgetstate| if (widgetstate.widget.dynamic_cast(Tab.ButtonType)) |btn| if (btn.drag_pos) |_|
+                tui.update_drag_source(&widgetstate.widget, drag_btn);
+        tui.refresh_hover(@src());
     }
 
     pub fn render(self: *Self, theme: *const Widget.Theme) bool {
@@ -153,7 +159,8 @@ pub const TabBar = struct {
         });
         self.plane.fill(" ");
         self.plane.home();
-        return self.widget_list_widget.render(theme);
+        for (self.tabs) |*tab| _ = tab.widget.render(theme);
+        return false;
     }
 
     pub fn receive(self: *Self, _: tp.pid_ref, m: tp.message) error{Exit}!bool {
@@ -200,14 +207,9 @@ pub const TabBar = struct {
                     if (btn.hover) break idx;
             } else return;
             if (dragging != hover_) {
-                const tmp = self.tabs[dragging];
+                self.swap_tabs_by_index(dragging, hover_);
-                self.tabs[dragging] = self.tabs[hover_];
-                self.tabs[hover_] = tmp;
                 if (self.tabs[dragging].widget.dynamic_cast(Tab.ButtonType)) |btn| btn.hover = false;
                 self.update();
-                for (self.widget_list.widgets.items) |*widgetstate| if (widgetstate.widget.dynamic_cast(Tab.ButtonType)) |btn| if (btn.drag_pos) |_|
-                    tui.update_drag_source(&widgetstate.widget);
-                tui.refresh_hover();
             }
         }
     }
@@ -229,30 +231,61 @@ pub const TabBar = struct {
         return self.widget_list_widget.hover();
     }
 
-    fn update_tabs(self: *Self) !void {
+    fn update_tabs(self: *Self, drag_source: ?*Widget) !void {
         const buffer_manager = tui.get_buffer_manager() orelse @panic("tabs no buffer manager");
-        try self.update_tab_buffers();
+        const buffers_changed = try self.update_tab_buffers();
-        const prev_widget_count = self.widget_list.widgets.items.len;
+        const dragging = for (self.tabs) |*tab| {
-        while (self.widget_list.pop()) |widget| if (widget.dynamic_cast(Tab.ButtonType) == null)
+            if (tab.widget.dynamic_cast(Tab.ButtonType)) |btn|
+                if (btn.drag_pos) |_| break true;
+        } else false;
+        if (!dragging and !buffers_changed and self.widget_list.widgets.items.len > 0) return;
+        var prev_widget_count: usize = 0;
+        for (self.widget_list.widgets.items) |*split_widgetstate| if (split_widgetstate.widget.dynamic_cast(WidgetList)) |split| {
+            prev_widget_count += 1;
+            for (split.widgets.items) |_| prev_widget_count += 1;
+        };
+
+        for (self.widget_list.widgets.items) |*split_widget| if (split_widget.widget.dynamic_cast(WidgetList)) |split| {
+            for (split.widgets.items) |*widget|
+                if (&widget.widget == drag_source) tui.reset_drag_context();
+        };
+        while (self.widget_list.pop()) |split_widget| if (split_widget.dynamic_cast(WidgetList)) |split| {
+            while (split.pop()) |widget| if (widget.dynamic_cast(Tab.ButtonType) == null)
                 widget.deinit(self.widget_list.allocator);
+            split.deinit(self.widget_list.allocator);
+        };
+
+        var max_view: usize = 0;
+        for (self.tabs) |tab| max_view = @max(max_view, tab.view orelse 0);
+
+        var widget_count: usize = 0;
+        for (0..max_view + 1) |view| {
             var first = true;
+            var view_widget_list = try WidgetList.createH(self.allocator, self.widget_list.plane, "split", .dynamic);
+            try self.widget_list.add(view_widget_list.widget());
+            widget_count += 1;
             for (self.tabs) |tab| {
+                const tab_view = tab.view orelse 0;
+                if (tab_view != view) continue;
                 if (first) {
                     first = false;
                 } else {
-                try self.widget_list.add(try self.make_spacer());
+                    try view_widget_list.add(try self.make_spacer(view_widget_list.plane));
+                    widget_count += 1;
                 }
-            try self.widget_list.add(tab.widget);
+                try view_widget_list.add(tab.widget);
+                widget_count += 1;
                 if (tab.widget.dynamic_cast(Tab.ButtonType)) |btn| {
                     if (buffer_manager.buffer_from_ref(tab.buffer_ref)) |buffer|
                         try btn.update_label(Tab.name_from_buffer(buffer));
                 }
             }
-        if (prev_widget_count != self.widget_list.widgets.items.len)
+        }
-            tui.refresh_hover();
+        if (prev_widget_count != widget_count)
+            tui.refresh_hover(@src());
     }
 
-    fn update_tab_buffers(self: *Self) !void {
+    fn update_tab_buffers(self: *Self) !bool {
         const buffer_manager = tui.get_buffer_manager() orelse @panic("tabs no buffer manager");
         const buffers = try buffer_manager.list_unordered(self.allocator);
         defer self.allocator.free(buffers);
@@ -278,6 +311,16 @@ pub const TabBar = struct {
         }
 
         self.tabs = try result.toOwnedSlice(self.allocator);
+
+        if (existing_tabs.len != self.tabs.len)
+            return true;
+        for (existing_tabs, self.tabs) |tab_a, tab_b| {
+            if (tab_a.buffer_ref == tab_b.buffer_ref and
+                tab_a.view == tab_b.view)
+                continue;
+            return true;
+        }
+        return false;
     }
 
     fn place_new_tab(self: *Self, result: *std.ArrayListUnmanaged(TabBarTab), buffer: *Buffer) !void {
@@ -295,14 +338,14 @@ pub const TabBar = struct {
             else
                 try result.addOne(self.allocator),
         };
-        pos.* = .{ .buffer_ref = buffer_ref, .widget = tab };
+        pos.* = .{ .buffer_ref = buffer_ref, .widget = tab, .view = buffer.get_last_view() };
         self.place_next = .atend;
     }
 
-    fn make_spacer(self: @This()) !Widget {
+    fn make_spacer(self: @This(), parent: Plane) !Widget {
         return spacer.create(
             self.allocator,
-            self.widget_list.plane,
+            parent,
             self.tab_style.spacer,
             self.tab_style.spacer_fg,
             self.tab_style.spacer_bg,
@@ -371,9 +414,23 @@ pub const TabBar = struct {
             tp.trace(tp.channel.debug, .{ "swap_tabs", "not_found", "buffer_ref_b" });
             return;
         };
+        self.swap_tabs_by_index(tab_a_idx, tab_b_idx);
+    }
+
+    fn swap_tabs_by_index(self: *Self, tab_a_idx: usize, tab_b_idx: usize) void {
         const tmp = self.tabs[tab_a_idx];
         self.tabs[tab_a_idx] = self.tabs[tab_b_idx];
         self.tabs[tab_b_idx] = tmp;
+        const buffer_manager = tui.get_buffer_manager() orelse @panic("tabs no buffer manager");
+        if (buffer_manager.buffer_from_ref(self.tabs[tab_a_idx].buffer_ref)) |buffer_a|
+            if (buffer_manager.buffer_from_ref(self.tabs[tab_b_idx].buffer_ref)) |buffer_b| {
+                const view_a = buffer_a.get_last_view();
+                const view_b = buffer_b.get_last_view();
+                if (view_a != view_b) {
+                    buffer_a.set_last_view(view_b);
+                    buffer_b.set_last_view(view_a);
+                }
+            };
         tp.trace(tp.channel.debug, .{ "swap_tabs", "swapped", "indexes", tab_a_idx, tab_b_idx });
     }
 
@@ -417,21 +474,27 @@ pub const TabBar = struct {
         while (count > 0) : (count -= 1) {
             var buffer_name: ?[]const u8 = undefined;
             if (!(cbor.matchValue(&iter2, cbor.extract(&buffer_name)) catch false)) return error.MatchTabBufferNameFailed;
-            if (buffer_name) |name| if (name_to_ref(name)) |buffer_ref| {
+            if (buffer_name) |name| {
+                const buffer_ref_, const buffer_view = name_to_ref_and_view(name);
+                if (buffer_ref_) |buffer_ref|
                     (try result.addOne(self.allocator)).* = .{
                         .buffer_ref = buffer_ref,
                         .widget = try Tab.create(self, buffer_ref, &self.tab_style),
+                        .view = buffer_view,
                     };
-            };
+            }
         }
 
         self.tabs = try result.toOwnedSlice(self.allocator);
         iter.* = iter2;
     }
 
-    fn name_to_ref(buffer_name: []const u8) ?usize {
+    fn name_to_ref_and_view(buffer_name: []const u8) struct { ?usize, ?usize } {
         const buffer_manager = tui.get_buffer_manager() orelse @panic("tabs no buffer manager");
-        return if (buffer_manager.get_buffer_for_file(buffer_name)) |buffer| buffer_manager.buffer_to_ref(buffer) else null;
+        return if (buffer_manager.get_buffer_for_file(buffer_name)) |buffer|
+            .{ buffer_manager.buffer_to_ref(buffer), buffer.get_last_view() }
+        else
+            .{ null, null };
     }
 };
 

src/tui/tui.zig

@@ -58,7 +58,7 @@ last_hover_y: c_int = -1,
 commands: Commands = undefined,
 logger: log.Logger,
 drag_source: ?*Widget = null,
-drag_button: ?input.MouseType = null,
+drag_button: input.MouseType = 0,
 dark_theme: Widget.Theme,
 dark_parsed_theme: ?std.json.Parsed(Widget.Theme),
 light_theme: Widget.Theme,
@@ -407,7 +407,7 @@ fn receive_safe(self: *Self, from: tp.pid_ref, m: tp.message) !void {
         };
         try self.dispatch_flush_input_event();
         if (self.unrendered_input_events_count > 0 and !self.frame_clock_running)
-            need_render();
+            need_render(@src());
         return;
     }
 
@@ -556,7 +556,7 @@ fn receive_safe(self: *Self, from: tp.pid_ref, m: tp.message) !void {
     if (try m.match(.{"MOUSE_IDLE"})) {
         if (self.mouse_idle_timer) |*t| t.deinit();
         self.mouse_idle_timer = null;
-        try self.clear_hover_focus();
+        try self.clear_hover_focus(@src());
         return;
     }
 
@@ -668,11 +668,13 @@ fn render(self: *Self) void {
         if (!self.frame_clock_running) {
             self.frame_clock.start() catch {};
             self.frame_clock_running = true;
+            tp.trace(tp.channel.widget, .{ "frame_clock_running", "started", more });
         }
     } else {
         if (self.frame_clock_running) {
             self.frame_clock.stop() catch {};
             self.frame_clock_running = false;
+            tp.trace(tp.channel.widget, .{ "frame_clock_running", "stopped", more });
         }
     }
 }
@@ -849,32 +851,34 @@ fn update_hover(self: *Self, y: c_int, x: c_int) !?*Widget {
     self.last_hover_x = x;
     if (y >= 0 and x >= 0) if (self.find_coord_widget(@intCast(y), @intCast(x))) |w| {
         if (if (self.hover_focus) |h| h != w else true) {
-            var buf: [256]u8 = undefined;
+            tp.trace(tp.channel.debug, .{ "update_hover", if (self.hover_focus) |h| @intFromPtr(h) else 0, @intFromPtr(w) });
-            if (self.hover_focus) |h| {
+            if (self.hover_focus) |h| if (self.is_live_widget_ptr(h))
-                if (self.is_live_widget_ptr(h))
+                try send_hover_msg(h, false);
-                    _ = try h.send(tp.self_pid(), tp.message.fmtbuf(&buf, .{ "H", false }) catch |e| return tp.exit_error(e, @errorReturnTrace()));
-            }
             self.hover_focus = w;
-            _ = try w.send(tp.self_pid(), tp.message.fmtbuf(&buf, .{ "H", true }) catch |e| return tp.exit_error(e, @errorReturnTrace()));
+            try send_hover_msg(w, true);
         }
         return w;
     };
-    try self.clear_hover_focus();
+    try self.clear_hover_focus(@src());
     return null;
 }
 
-fn clear_hover_focus(self: *Self) tp.result {
+fn clear_hover_focus(self: *Self, src: std.builtin.SourceLocation) tp.result {
-    if (self.hover_focus) |h| {
+    if (self.hover_focus) |h| if (self.is_live_widget_ptr(h))
-        var buf: [256]u8 = undefined;
+        try send_hover_msg(h, false);
-        if (self.is_live_widget_ptr(h))
+    tp.trace(tp.channel.debug, .{ "tui", "clear_hover_focus", if (self.hover_focus) |h| @intFromPtr(h) else 0, src.fn_name, src.file, src.line });
-            _ = try h.send(tp.self_pid(), tp.message.fmtbuf(&buf, .{ "H", false }) catch |e| return tp.exit_error(e, @errorReturnTrace()));
-    }
     self.hover_focus = null;
 }
 
-pub fn refresh_hover() void {
+fn send_hover_msg(widget: *const Widget, hover: bool) tp.result {
+    var buf: [256]u8 = undefined;
+    tp.trace(tp.channel.debug, .{ "hover_msg", @intFromPtr(widget), hover });
+    _ = try widget.send(tp.self_pid(), tp.message.fmtbuf(&buf, .{ "H", hover }) catch |e| return tp.exit_error(e, @errorReturnTrace()));
+}
+
+pub fn refresh_hover(src: std.builtin.SourceLocation) void {
     const self = current();
-    self.clear_hover_focus() catch return;
+    tp.trace(tp.channel.debug, .{ "tui", "refresh_hover", if (self.hover_focus) |h| @intFromPtr(h) else 0, src.fn_name, src.file, src.line });
     _ = self.update_hover(self.last_hover_y, self.last_hover_x) catch {};
 }
 
@@ -898,7 +902,7 @@ fn enter_overlay_mode(self: *Self, mode: type) command.Result {
     self.input_mode_outer_ = self.input_mode_;
     self.input_mode_ = new_mode;
     if (self.input_mode_) |*m| m.run_init();
-    refresh_hover();
+    refresh_hover(@src());
 }
 
 fn enter_overlay_mode_with_args(self: *Self, mode: type, ctx: command.Context) command.Result {
@@ -910,7 +914,7 @@ fn enter_overlay_mode_with_args(self: *Self, mode: type, ctx: command.Context) c
     self.input_mode_outer_ = self.input_mode_;
     self.input_mode_ = try mode.create_with_args(self.allocator, ctx);
     if (self.input_mode_) |*m| m.run_init();
-    refresh_hover();
+    refresh_hover(@src());
 }
 
 fn get_input_mode(self: *Self, mode_name: []const u8) !Mode {
@@ -1386,7 +1390,7 @@ const cmds = struct {
         if (self.input_mode_) |*mode| mode.deinit();
         self.input_mode_ = self.input_mode_outer_;
         self.input_mode_outer_ = null;
-        refresh_hover();
+        refresh_hover(@src());
     }
     pub const exit_overlay_mode_meta: Meta = .{};
 
@@ -1613,21 +1617,21 @@ const cmds = struct {
 
     pub fn panel_next_widget_style(_: *Self, _: Ctx) Result {
         set_next_style(.panel);
-        need_render();
+        need_render(@src());
         try save_config();
     }
     pub const panel_next_widget_style_meta: Meta = .{};
 
     pub fn hint_window_next_widget_style(_: *Self, _: Ctx) Result {
         set_next_style(.hint_window);
-        need_render();
+        need_render(@src());
         try save_config();
     }
     pub const hint_window_next_widget_style_meta: Meta = .{};
 
     pub fn dropdown_next_widget_style(_: *Self, _: Ctx) Result {
         set_next_style(.dropdown);
-        need_render();
+        need_render(@src());
         try save_config();
     }
     pub const dropdown_next_widget_style_meta: Meta = .{};
@@ -1775,9 +1779,10 @@ pub fn get_keybind_mode() ?Mode {
     return self.input_mode_ orelse self.delayed_init_input_mode;
 }
 
-pub fn update_drag_source(drag_source: *Widget) void {
+pub fn update_drag_source(drag_source: *Widget, btn: input.MouseType) void {
     const self = current();
     self.drag_source = drag_source;
+    self.drag_button = btn;
 }
 
 fn set_drag_source(self: *Self, drag_source: ?*Widget, btn: input.MouseType) void {
@@ -1785,6 +1790,11 @@ fn set_drag_source(self: *Self, drag_source: ?*Widget, btn: input.MouseType) voi
     self.drag_button = btn;
 }
 
+pub fn get_drag_source() struct { ?*Widget, input.MouseType } {
+    const self = current();
+    return .{ self.drag_source, self.drag_button };
+}
+
 pub fn reset_drag_context() void {
     const self = current();
     self.drag_source = null;
@@ -1797,9 +1807,10 @@ fn maybe_reset_drag_source(self: *Self, btn: input.MouseType) void {
     self.drag_button = 0;
 }
 
-pub fn need_render() void {
+pub fn need_render(src: std.builtin.SourceLocation) void {
     const self = current();
     if (!(self.render_pending or self.frame_clock_running)) {
+        tp.trace(tp.channel.debug, .{ "tui", "need_render", src.fn_name, src.file, src.line });
         self.render_pending = true;
         tp.self_pid().send(.{"render"}) catch {};
     }
@@ -1812,8 +1823,8 @@ pub fn frames_rendered() usize {
 
 pub fn resize() void {
     mainview_widget().resize(screen());
-    refresh_hover();
+    refresh_hover(@src());
-    need_render();
+    need_render(@src());
 }
 
 pub fn plane() renderer.Plane {