Restore instrument window size

May be, this is a known issue but please let me explain again.

If you replace an existing SlicerT instrument with new one by dragging it over the instrument setting, following can be seen ~~due to size not restored~~. In this example, I replaced a track from SlicerT to SID.


Reproduce the issue by replacing an existing SlicerT instrument with a SID instrument through the instrument setting, then observe whether the instrument window size is restored. The work is done when replacing the instrument preserves or restores the expected window size; a linked pull request has already been merged.

Written by the indexing model from the issue text.