compdfkit(win) - 切换模块和重启文档时undo redo 历史清除

Demo/Examples/Compdfkit_Tools/DigitalSignature/DigitalSignatureControl/DigitalSignatureControl.xaml.cs

@@ -113,6 +113,8 @@ namespace Compdfkit_Tools.PDFControl
             
             panelState.PropertyChanged -= PanelState_PropertyChanged;
             panelState.PropertyChanged += PanelState_PropertyChanged;
+
+            PDFViewControl.PDFView.UndoManager.ClearHistory();
         }
         
         public void LoadUndoManagerEvent(CPDFViewer pdfViewer)