[gtk/tooltip-redo: 57/57] docs: Mention custom tooltip windows in the migration guide

[Matthias Clasen <matthiasc src gnome org>]

commit 156935e0e902ec31e6353556c2456804816f0691
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Dec 29 20:57:05 2019 -0500

    docs: Mention custom tooltip windows in the migration guide
    
    These no longer exist.

 docs/reference/gtk/migrating-3to4.xml | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/docs/reference/gtk/migrating-3to4.xml b/docs/reference/gtk/migrating-3to4.xml
index c7fa65e835..d64261eee7 100644
--- a/docs/reference/gtk/migrating-3to4.xml
+++ b/docs/reference/gtk/migrating-3to4.xml
@@ -893,6 +893,16 @@
         radioitem as proxy.
       </para>
     </section>
+
+    <section>
+      <title>Stop using custom tooltip windows</title>
+      <para>
+        Tooltips no longer use GtkWindows in GTK 4, and it is no longer
+        possible to provide a custom window for tooltips. Replacing the content
+        of the tooltip with a custom widget is still possible, with
+        gtk_tooltip_set_custom().
+      </para>
+    </section>
   </section>
 
 </chapter>