Fallback proc & Issue templates

code/modules/tgui/external.dm

@@ -82,6 +82,17 @@
 	if(!ui || ui.status != STATUS_INTERACTIVE)
 		return TRUE
 
+/**
+ * public
+ *
+ * Called on a UI when the UI crashed.
+ *
+ * required payload list A list of the payload supposed to be set on the regular UI.
+ */
+/datum/proc/tgui_fallback(list/payload)
+	SHOULD_CALL_PARENT(TRUE)
+	SEND_SIGNAL(src, COMSIG_UI_FALLBACK, usr)
+
 /**
  * public
  *