Deleting files in a zip Next
toolbar icon for deleting a file Menu : Edit > Delete...

The delete dialog

The delete function gives you the following choices...
  - All items - All items in the archive are deleted.
  - Selected items - The selected items are deleted
  - Files - Any file in the archive that matches this filter will be deleted.

Results
The number of files deleted will be shown in the status bar.

Note
The files are not actually deleted from the archive until you save your changes.