Fix potential pop of empty enter stack.

diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index 6f22199d661a727558e52bbd171924170b27bf3d..9edef8056ed5f99988b6c77b012dc1a9c7c67f20 100644 (file)
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -1651,7 +1651,9 @@ Editor::leave_handler (ArdourCanvas::Item* item, GdkEvent*, ItemType item_type)
        bool is_start;
        bool ret = true;
 
-       _enter_stack.pop_back();
+       if (!_enter_stack.empty()) {
+               _enter_stack.pop_back();
+       }
 
        switch (item_type) {
        case ControlPointItem: