File/Open and File/New closes all GroupNodes now to fix

NullPointerExceptions

src/ui/view/GUI.java

@@ -2048,7 +2048,11 @@ public class GUI{
 					mntmSave.doClick();
 				}
 			}
-
+			//Remove all but main tab
+			while(tabbedPaneInnerOriginal.getTabCount() > 1) {
+				tabbedPaneInnerOriginal.remove(1);
+			}
+			model.getSelectedCpsObjects().clear();
 			model.getEdgesOnCanvas().removeAll(model.getEdgesOnCanvas());
 			model.getObjectsOnCanvas().removeAll(model.getObjectsOnCanvas());
 			controller.setSelectedObjectID(0);
@@ -2080,6 +2084,10 @@ public class GUI{
 					File file = fileChooser.getSelectedFile();
 
 					try {
+						while(tabbedPaneInnerOriginal.getTabCount() > 1) {
+							tabbedPaneInnerOriginal.remove(1);
+						}
+						model.getSelectedCpsObjects().clear();
 						controller.loadFile(file.getAbsolutePath());
 						canvas.repaint();
 						categoryTree.repaint();