When using the browser for drawing, some cache will be generated. When the browser cache increases, this situation may occur when opening plans. If this happens, please save your plan first and then follow the steps below to clear the cache:

If you are using Google Chrome,

1.The shortcut key to clear the browser cache is Ctrl+Shift+Delete.
2.After clearing both the "Basic" and "Advanced" sections, close the browser and log in again to continue using it (if you need to clear saved passwords, please check the appropriate option).