--- a/ui/gtk/container.h	Thu Dec 11 20:07:16 2025 +0100
+++ b/ui/gtk/container.h	Thu Dec 11 20:58:33 2025 +0100
@@ -61,6 +61,13 @@
     int close;
 };
 
+typedef struct UiCustomContainer {
+    UiContainerPrivate container;
+    UiObject *obj;
+    ui_addwidget_func add;
+    void *userdata;
+} UiCustomContainer;
+
 typedef struct UiBoxContainer {
     UiContainerPrivate container;
     UiSubContainerType type;