diff --git a/src/Undo.cpp b/src/Undo.cpp
index ac655cd71c..eec7ff4466 100644
--- a/src/Undo.cpp
+++ b/src/Undo.cpp
@@ -253,6 +253,7 @@ bool Undo::hasRedoStack() const
 
 void Undo::markDirty()
 {
+	d->undo_finished_ = true;
 	d->undostack_.markDirty();
 	d->redostack_.markDirty();	
 }