runtime(doc): Add gtk4-slow doc tag

closes: #20432

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/runtime/doc/gui_x11.txt b/runtime/doc/gui_x11.txt
index fce4fb47c4882bebd7b1af0efd88c9b79821a602..5f8056bebac97b2953373f6be6dc306b30f9df52 100644 (file)
--- a/runtime/doc/gui_x11.txt
+++ b/runtime/doc/gui_x11.txt
@@ -1,4 +1,4 @@
-*gui_x11.txt*  For Vim version 9.2.  Last change: 2026 Feb 14
+*gui_x11.txt*  For Vim version 9.2.  Last change: 2026 Jun 07
 
 
                  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -356,6 +356,17 @@ for more information.
 If you are using GTK3 and Vim appears to be slow, try setting the environment
 variable $GDK_RENDERING to "image".
 
+                                                       *gtk4-slow*
+If the GTK4 GUI is slow, freezes, or does not accept keyboard input right
+after startup, it may be caused by the OpenGL renderer or GPU driver.  Try
+starting gvim with one of the following environment variables.  Setting
+$GSK_RENDERER to "cairo" disables the GSK OpenGL renderer.  Setting
+$LIBGL_ALWAYS_SOFTWARE to "true" retains the OpenGL renderer but forces Mesa
+to use software rendering: >
+
+    $ GSK_RENDERER=cairo gvim
+    $ LIBGL_ALWAYS_SOFTWARE=true gvim
+
 
 Tooltip Colors ~
                                                        *gtk-tooltip-colors*

diff --git a/runtime/doc/tags b/runtime/doc/tags
index 33c6daa42b0fe1f1453295e9a7d10f554517bca4..a2b4743a86e53a1337e69aa1be72ce1a050cf69a 100644 (file)
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -8248,6 +8248,7 @@ gt        tabpage.txt     /*gt*
 gtk-css        gui_x11.txt     /*gtk-css*
 gtk-tooltip-colors     gui_x11.txt     /*gtk-tooltip-colors*
 gtk3-slow      gui_x11.txt     /*gtk3-slow*
+gtk4-slow      gui_x11.txt     /*gtk4-slow*
 gu     change.txt      /*gu*
 gugu   change.txt      /*gugu*
 gui    gui.txt /*gui*