patch 9.2.0397: tabpanel: double-click opens a new tab

Problem:  tabpanel: double-click opens a new tab page
Solution: Do not create a new tab page when using a double click
          (Yasuhiro Matsumoto).

The tabpanel click handler inherited the tabline behavior where a
double-click opens a new, empty tab page.  Unlike the tabline, the
tabpanel has no "empty area": every row maps to some tab, so this
fires on any double-click in the tabpanel and can generate stray
empty tabs.  The behavior is also not documented for the tabpanel.

Skip the new-tab branch when the click originated in the tabpanel
and fall through to the regular tab-switch path instead.  The
tabline behavior is unchanged.

closes: #20044

Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/tabpage.txt

@@ -1,4 +1,4 @@
-*tabpage.txt*	For Vim version 9.2.  Last change: 2026 Apr 25
+*tabpage.txt*	For Vim version 9.2.  Last change: 2026 Apr 26
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -513,6 +513,16 @@ The scrollbar uses the |hl-PmenuSbar| highlight group for the track and
 The scroll offset is remembered across redraws but is reset when "scroll" or
 "scrollbar" is toggled off and back on.
 
+MOUSE CLICKS IN THE TABPANEL:				*tabpanel-mouse*
+
+A left click on a row in the tabpanel selects the tab page that the row
+belongs to.  Unlike the tabline, a double click in the tabpanel does not
+open a new, empty tab page; it is treated the same as a single click.
+
+For finer-grained control, the 'tabpanel' value may contain |stl-%[FuncName]|
+click regions.  Clicks on those regions are dispatched to the callback
+function instead of falling through to tab selection.
+
 ==============================================================================
 6. Setting 'guitablabel'				*setting-guitablabel*
 

runtime/doc/tags

@@ -10893,6 +10893,7 @@ tabpagebuflist()	builtin.txt	/*tabpagebuflist()*
 tabpagenr()	builtin.txt	/*tabpagenr()*
 tabpagewinnr()	builtin.txt	/*tabpagewinnr()*
 tabpanel	tabpage.txt	/*tabpanel*
+tabpanel-mouse	tabpage.txt	/*tabpanel-mouse*
 tabpanel-scroll	tabpage.txt	/*tabpanel-scroll*
 tag	tagsrch.txt	/*tag*
 tag-!	tagsrch.txt	/*tag-!*

src/mouse.c

@@ -591,9 +591,13 @@ do_mouse(
 	    c1 = tp_label.nr;
 	    if (c1 >= 0)
 	    {
-		if ((mod_mask & MOD_MASK_MULTI_CLICK) == MOD_MASK_2CLICK)
+		if ((mod_mask & MOD_MASK_MULTI_CLICK) == MOD_MASK_2CLICK
+						    && !tp_label.is_panel)
 		{
-		    // double click opens new page
+		    // Double-click on the tabline opens a new, empty tab page.
+		    // The tabpanel has no "empty area" (every row maps to a tab)
+		    // and this behavior is not documented for tabpanel, so fall
+		    // through to the regular tab-switch path there.
 		    end_visual_mode_keep_button();
 		    tabpage_new();
 		    tabpage_move(c1 == 0 ? 9999 : c1 - 1);

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    397,
 /**/
     396,
 /**/