[Feature]: Add select none or invert selection button

[nettnikl]

Feature Description

If all items are selected, eg. using the select all button, the select all button loses it's functionality. Maybe it should be replaced by a select none or invert selection button.

How can this feature be implemented?

• If in selection mode, we should listen to those when the selection is being changed
• If everything is in the selection, set another text for the button
• If everything is in the selection, and the button is clicked, do it differently

Duplicate feature

• [X] This feature has not been requested yet.