Reported in TWiki:Support.LeaseFileNotBeingDeleted
When editing any topic with the WYSIWYG plugin, if you press CANCEL (the red button) the .lease file under data/ won't be deleted, as it happens when you edit with the old EDIT method. That means the user will still hold on to that lease even after having abandoned the changes, and any other users who want to edit it will have the warning "Another user is currently editing this" displayed to them. Shouldn't the behaviour be the same as with the old EDIT method, when the lease is immediately cancelled if the user selects "Cancel"?
Should be fixed now. Marking as Waiting for Release as this is part of the standard package.