If a track is selected, unselect any selected parts #998

i selected a track to delete it with the Del key but it deleted a MIDI part I selected previously.

Selecting a track without Ctrl should unselect all other selections, including parts.

To replicate it:

1. Crate 2 tracks, one Wave (Track 1) one MIDI (Track 2)
2. Draw a random MIDI clip with the Draw tool
3. Left-click on the MIDI clip
4. Left click on the audio track
5. Press the Del key
6. The MIDI part in Track 2 will be deleted, even if the last action the user did is explicitly select Track 1