I also tried to apply the "Alt" key to a button and hoping I could use the dial to control sharpness and especially the masking under sharpenig which would display a black and white image. To no avail.
But why I reply, the case you describe about selecting images to sync, stack or any other processing. You can assign "Select To The Right", "Left" or "Right and Left" to a button. You will find it under "General" when assigning button controls in Midi2LR. I use it and have assigned "Ctrl-g" to another button for HDR stacking.
On Wednesday, October 3, 2018 at 6:10:19 AM UTC+2, efong wrote: