--- a/ui/gtk/toolkit.h	Sun Jun 16 10:42:22 2024 +0200
+++ b/ui/gtk/toolkit.h	Sun Jun 16 11:23:21 2024 +0200
@@ -55,9 +55,11 @@
     void        *userdata;
 } UiVarEventData;
 
+#ifndef UI_GTK4
 struct UiSelection {
     GtkSelectionData *data;
 };
+#endif
 
 typedef enum UiOrientation UiOrientation;
 enum UiOrientation { UI_HORIZONTAL = 0, UI_VERTICAL };