Path tool box selection creates small square upon mousedown when animation is playing

1. Switch to the Path tool
2. Hit play to start animation playback
3. Click but don't drag or release— notice how the box selection surrounds the pointer with a small square:

Reproduce the issue with the Path tool while animation playback is running, following the three steps in the report. Trace the Path tool's box-selection handling during mousedown and compare it with playback stopped; done means a click without dragging no longer creates a small selection square.

Written by the indexing model from the issue text.