diff --git a/src/gui/wio/app.zig b/src/gui/wio/app.zig
index 61ec5a23..0cd9edcd 100644
--- a/src/gui/wio/app.zig
+++ b/src/gui/wio/app.zig
@@ -490,17 +490,22 @@ fn wioLoop() void {
                             cp.yoff,
                         }) catch {};
                     } else {
-                        const base_cp = input_translate.codepointFromButton(btn, .{});
-                        const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
-                        if (base_cp != 0) sendKey(1, base_cp, shifted_cp, mods);
+                        if (input_translate.codepointFromButton(btn, .{})) |base_cp| {
+                            const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
+                            sendKey(1, base_cp, shifted_cp orelse base_cp, mods);
+                        } else {
+                            if (input_translate.modifierCodepoint(btn)) |mod_cp|
+                                sendKey(1, mod_cp, mod_cp, mods);
+                        }
                     }
                 },
                 .button_repeat => |btn| {
                     const mods = input_translate.Mods.fromButtons(held_buttons);
                     if (input_translate.mouseButtonId(btn) == null) {
-                        const base_cp = input_translate.codepointFromButton(btn, .{});
-                        const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
-                        if (base_cp != 0) sendKey(2, base_cp, shifted_cp, mods);
+                        if (input_translate.codepointFromButton(btn, .{})) |base_cp| {
+                            const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
+                            sendKey(2, base_cp, shifted_cp orelse base_cp, mods);
+                        }
                     }
                 },
                 .button_release => |btn| {
@@ -518,9 +523,12 @@ fn wioLoop() void {
                             cp.yoff,
                         }) catch {};
                     } else {
-                        const base_cp = input_translate.codepointFromButton(btn, .{});
-                        const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
-                        if (base_cp != 0) sendKey(3, base_cp, shifted_cp, mods);
+                        if (input_translate.codepointFromButton(btn, .{})) |base_cp| {
+                            const shifted_cp = if (mods.shift) input_translate.codepointFromButton(btn, .{ .shift = true }) else base_cp;
+                            sendKey(3, base_cp, shifted_cp orelse base_cp, mods);
+                        } else if (input_translate.modifierCodepoint(btn)) |mod_cp| {
+                            sendKey(3, mod_cp, mod_cp, mods);
+                        }
                     }
                 },
                 .char => |cp| {
@@ -557,6 +565,18 @@ fn wioLoop() void {
                 },
                 .unfocused => {
                     window.disableTextInput();
+                    // Synthesize release events for any modifier keys still held so the TUI
+                    // doesn't see them as stuck. Release in order so mods reflects reality after
+                    // each release.
+                    for (input_translate.modifier_buttons) |mod_btn| {
+                        if (held_buttons.has(mod_btn)) {
+                            held_buttons.release(mod_btn);
+                            const mods = input_translate.Mods.fromButtons(held_buttons);
+                            if (input_translate.modifierCodepoint(mod_btn)) |mod_cp|
+                                sendKey(3, mod_cp, mod_cp, mods);
+                        }
+                    }
+                    held_buttons = .{};
                     tui_pid.send(.{"focus_out"}) catch {};
                 },
                 else => {},
diff --git a/src/gui/wio/input.zig b/src/gui/wio/input.zig
index 0d2a6fe9..4c22e413 100644
--- a/src/gui/wio/input.zig
+++ b/src/gui/wio/input.zig
@@ -58,7 +58,7 @@ pub const KeyEvent = struct {
 };
 
 // Map a wio.Button to the primary codepoint for that key
-pub fn codepointFromButton(b: wio.Button, mods: Mods) u21 {
+pub fn codepointFromButton(b: wio.Button, mods: Mods) ?u21 {
     return switch (b) {
         .a => if (mods.shiftOnly()) 'A' else 'a',
         .b => if (mods.shiftOnly()) 'B' else 'b',
@@ -153,7 +153,7 @@ pub fn codepointFromButton(b: wio.Button, mods: Mods) u21 {
         .kp_plus => vaxis.Key.kp_add,
         .kp_enter => vaxis.Key.kp_enter,
         .kp_equals => vaxis.Key.kp_equal,
-        else => 0,
+        else => null,
     };
 }
 
@@ -161,6 +161,32 @@ pub const mouse_button_left: u8 = 0;
 pub const mouse_button_middle: u8 = 1;
 pub const mouse_button_right: u8 = 2;
 
+// Map modifier wio.Button values to kitty protocol codepoints (vaxis.Key.*).
+// Returns 0 for non-modifier buttons.
+pub fn modifierCodepoint(b: wio.Button) ?u21 {
+    return switch (b) {
+        .left_shift => vaxis.Key.left_shift,
+        .left_control => vaxis.Key.left_control,
+        .left_alt => vaxis.Key.left_alt,
+        .left_gui => vaxis.Key.left_super,
+        .right_shift => vaxis.Key.right_shift,
+        .right_control => vaxis.Key.right_control,
+        .right_alt => vaxis.Key.right_alt,
+        .right_gui => vaxis.Key.right_super,
+        .caps_lock => vaxis.Key.caps_lock,
+        .num_lock => vaxis.Key.num_lock,
+        .scroll_lock => vaxis.Key.scroll_lock,
+        else => null,
+    };
+}
+
+// All buttons that contribute to modifier state, for unfocus cleanup.
+pub const modifier_buttons = [_]wio.Button{
+    .left_shift,  .left_control,  .left_alt,    .left_gui,
+    .right_shift, .right_control, .right_alt,   .right_gui,
+    .caps_lock,   .num_lock,      .scroll_lock,
+};
+
 pub fn mouseButtonId(b: wio.Button) ?u8 {
     return switch (b) {
         .mouse_left => mouse_button_left,