merged with master

undo/undo.cpp

@@ -1136,7 +1136,7 @@ void OliveAction::undo() {
   doUndo();
 
   if (set_window_modified) {
-    olive::MainWindow->setWindowModified(old_window_modified);
+    olive::Global->set_modified(old_window_modified);
   }
 }
 
@@ -1146,10 +1146,10 @@ void OliveAction::redo() {
   if (set_window_modified) {
 
     // store current modified state
-    old_window_modified = olive::MainWindow->isWindowModified();
+    old_window_modified = olive::Global->is_modified();
 
     // set modified to true
-    olive::MainWindow->setWindowModified(true);
+    olive::Global->set_modified(true);
 
   }
 }