--- a/ui/common/context.h	Sun Dec 07 11:51:01 2025 +0100
+++ b/ui/common/context.h	Sun Dec 07 11:59:21 2025 +0100
@@ -84,8 +84,10 @@
     GtkAccelGroup *accel_group;
 #endif 
 #endif
-
-
+    
+    // allow only one document to be attached
+    // attaching a document will automatically detach the current document
+    UiBool single_document_mode;
     
     ui_callback   close_callback;
     void          *close_data;