Grid.

Solution:

1. Click "Start-Search-Select Pane" to select one of the objects, and then automatically locate it. If the located object is invisible to us, then it can be judged as a "hidden object", and we only need to select "right-click-delete" all objects.

2. Click "Featured Application-File Slimming" (at present, only members can use this function). Using file slimming can automatically delete such "hidden objects" in documents, saving the trouble of manual operation.