web part – quickedit doesn’t work in webpart while it works in the list

I created a list. Its quick edit mode works fine.
I placed this list into a webpart on a display/edit form and when we try to use quick edit we get this message:
“Invalid file name.

The file name you specified could not be used. It may be the name of an existing file or directory, or you may not have permission to access the file.”

It is not clear what happen. Can you explain what can be the difference in the two quick edit mode? The permissions are the same.