When the picker mode is entered with an unambiguous modifier key, e.g. Ctrl when other button mapping which use Ctrl are removed from the config, releasing the Ctrl key does not exit the mode as it should. Steps to reproduce:

1. Start with a blank config

2. Edit > Preferences > Buttons, and remove all mappings which use <Primary> (or <Control>) other than "Pick Color". This makes the Ctrl key unambiguously bound to the action, which means the hander takes a shortcut and enters the mode directly.

3. Press OK, and then try to pick using Ctrl.

Expected behaviour: pressing Ctrl enters the picker mode, and releasing it exits picker mode (even when you haven't picked anything with a button-press).

Observed behaviour: pressing Ctrl enters the picker mode, but releasing it does not exit picker mode when you haven't picked anything. The desired springload behaviour (mode exists when both Ctrl and the initiating button are released) only occurs after the first button press.

Setting as minor because the picker mode still works, and can be exited using normal user input related to its use.