emacs-28 29fdc65 1/2: Fix tab bar item highlight when a mouse click is dropped

[Juri Linkov]

branch: emacs-28
commit 29fdc65860e95a6e1c74147a3d310878080f6118
Author: Po Lu <luangruo@yahoo.com>
Commit: Juri Linkov <juri@linkov.net>

    Fix tab bar item highlight when a mouse click is dropped
    
    * src/xdisp.c (note_mouse_highlight): Clear last_tab_bar_item if the
    movement wasn't made on top of the tab bar.
---
 src/xdisp.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/xdisp.c b/src/xdisp.c
index 67946a5..97ba672 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -33652,6 +33652,14 @@ note_mouse_highlight (struct frame *f, int x, int y)
       else
        return;
     }
+  else
+    {
+      /* The mouse might have pressed into the tab bar, but might
+        also have been released outside the tab bar, so
+        f->last_tab_bar_item must be reset, in order to make sure the
+        item can be still highlighted again in the future.  */
+      f->last_tab_bar_item = -1;
+    }
 #endif
 
 #if defined (HAVE_WINDOW_SYSTEM) && ! defined (HAVE_EXT_TOOL_BAR)