Hi Juraj,

re:
> It happened to me many times that I wanted to trim complex shape and had to select like 50 small lines
> but one miss-click would deselect everything making user start from the beginning.

You don't have to start from the beginning if you make a selection mistake like that, you can just use undo which will restore the selection to whatever it was before the last selection action.

This "selection undo" is transient, it is only stored as the most recent action in the undo stack.

Also if you want to do deselect all, there is already a button for that on the side pane under Select > "Deselect all". If you would like to make a shortcut key for it, put in this for the command part of the shortcut key:

script: moi.geometryDatabase.deselectAll();

- Michael