diff --git a/demo-single-app/src/basic/MainFrame.java b/demo-single-app/src/basic/MainFrame.java
index 0c24c55..e77b457 100644
--- a/demo-single-app/src/basic/MainFrame.java
+++ b/demo-single-app/src/basic/MainFrame.java
@@ -162,7 +162,7 @@ public void setVisible(boolean visible) {
 
 		menuBar.add(window);
 
-		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+		setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
 
 		SimplePanel one = new SimplePanel("one", "one");
 		SimplePanel two = new SimplePanel("two", "two");
diff --git a/docking-api/src/ModernDocking/api/AppStateAPI.java b/docking-api/src/ModernDocking/api/AppStateAPI.java
index 0947091..aabbb2f 100644
--- a/docking-api/src/ModernDocking/api/AppStateAPI.java
+++ b/docking-api/src/ModernDocking/api/AppStateAPI.java
@@ -128,7 +128,7 @@ public void persist() {
 				@Override
 				public void actionPerformed(ActionEvent e) {
 					// we might have gotten to the timer and then paused persistence
-					if (!paused) {
+					if (!paused && docking.getRootPanels().containsKey(docking.getMainWindow())) {
 						ApplicationLayout layout = docking.getDockingState().getApplicationLayout();
 
 						try {