It would be handy to be able to adjust receive audio levels when in "Idle" mode or the "Waiting to start" state.
Since I use my PC and rig for other thing besides WSPR, the levels always have to be adjusted. I can get the transmit levels set in "Idle" mode, but have to wait 'til I'm actually "Receiving" before I can get the receive audio set.
Since my timing and luck are both naturally bad, this means I almost always have to sit and stare at the screen for two minutes 'til I get out of the "Waiting to start" state.