REPORT-6270 & REPORT-6443 参数面板里的相关bug（问题2、3）；控件树消失问题

designer-form/src/com/fr/design/mainframe/JForm.java

@@ -255,6 +255,9 @@ public class JForm extends JTemplate<Form, FormUndoState> implements BaseJForm {
             private XComponent lastAffectedCreator;
             @Override
             public void fireCreatorModified(DesignerEvent evt) {
+                if (formDesign.getArea() == null || !formDesign.getArea().isValid()) {
+                    return;
+                }
                 if (evt.getCreatorEventID() == DesignerEvent.CREATOR_CUTED) {
                     setPropertyPaneChange(formDesign.getRootComponent());
                 } else if (evt.getCreatorEventID() == DesignerEvent.CREATOR_DELETED) {