diff -r b25f54b51d76 -r d6baaa93f7be ui/gtk/container.c
--- a/ui/gtk/container.c	Sun Jul 13 11:02:45 2025 +0200
+++ b/ui/gtk/container.c	Sun Jul 13 11:38:27 2025 +0200
@@ -706,6 +706,7 @@
     event.document = event.obj->ctx->document;
     event.set = ui_get_setop();
     event.eventdata = NULL;
+    event.eventdatatype = 0;
     event.intval = page_num;
     
     tabview->onchange(&event, tabview->onchange);
@@ -728,6 +729,7 @@
     event.document = event.obj->ctx->document;
     event.set = ui_get_setop();
     event.eventdata = NULL;
+    event.eventdatatype = 0;
     event.intval = 0;
     
     tabview->onchange(&event, tabview->onchange);