This came along when i was messing around with the Physical Modeling instruments and i discovered that are the most CPU demanding amongst all. (As expected of course).
It could be very handy if an on/off switch (just like the effects), could be present to disable these that are not in use, and save CPU. Of course this is useful for every instrument as well.
Under the master section, there is space to fit this switch on the left side and move the M (mute) switch closer to S (solo). Just a suggestion!