Pane click doesn’t activate the correct pane on macOS when window is inactive

[zzhaolei]

When a kitty window has multiple panes (e.g., A | B) and is in the background, clicking on a non-active pane only activates the window — the clicked pane doesn't get focus. A second click is needed to actually switch.

This is because acceptsFirstMouse: in glfw/cocoa_window.m returns NO, which tells macOS to not deliver the mouseDown: event on the first click when the window is inactive. I noticed that iTerm2 and Ghostty both handle this by activating the clicked pane on the first click.

diff --git a/glfw/cocoa_window.m b/glfw/cocoa_window.m
index c72a89dbb..5b2a4c4fe 100644
--- a/glfw/cocoa_window.m
+++ b/glfw/cocoa_window.m
@@ -1015,7 +1015,7 @@ - (void)cursorUpdate:(NSEvent *)event
 - (BOOL)acceptsFirstMouse:(NSEvent *)event
 {
     (void)event;
-    return NO;  // changed by Kovid, to follow cocoa platform conventions
+    return YES;  // changed by Kovid, to follow cocoa platform conventions
 }

 - (void)mouseDown:(NSEvent *)event

Would it be acceptable to change this behavior?

[kovidgoyal]

See #9734 as I understand it is is platform convention on macOS for clicks in a non focused OS Window to not take effect on controls in that window.

[zzhaolei]

I tested Chrome, Zed, Safari, etc. after seeing #9734 and I think the mac may have changed its previous behavior? Now when you click on a label in an inactive window, you can directly activate the label under the mouse cursor.

[kovidgoyal]

OK, if the platform behavior has changed I have no issue changing kitty to match.