EClientSelection: Disallow drop into a read-only client
I setup a collection - CalDAV only - account for aaa@aegee.org
with password abc. The user has Tasks lists: OMS (read-only) and Default (read-write). With the mouse I move a task from the OMS task list to the Default task list. In the bottom Evolution writes “Moving”. Evolution-calendar-factory issues a PUT, receives 201 Created. It does not issue DELETE, but apparently Evolution knows that the task list is read-only. Evolution shows the error (in the top):
Failed to move a task into the task list “aaa@aegee.org : Default”
Cannot remove calendar object: Permission denied”
I suggest either to trigger by mouse only a Copy, but not a Move operation, showing the corresponding icon (as if the Ctrl key is implicitly pressed), when the source is read-only. Or visiually do not allow moving, unless the Crtl key is pressed, by providing some hints to the user to press Ctrl.
In the opposite direction, when a task is moved from Default to OMS, Evolution shall change the mouse cursor to show that the read-only OMS cannot be used as destination. Currently is issues an error, after the mouse button is released.