PDFView(Windows) - 修复右键菜单无法复制选取文字的问题

compdfkit_demo_windows/compdfkit/viewer-ctrl-demo/MainWindow.xaml.cs

@@ -230,6 +230,11 @@ namespace viewer_ctrl_demo
                     e.PopupMenu.Items.Add(doubleContinuousView);
                 }
             }
+
+            if (e != null && e.CommandType == CommandType.Copy)
+            {
+                e.DoCommand();
+            }
         }
 
         private void PasswordUI_Confirmed(object sender, string e)