You might be able to do some simple math OnSize to check height, and at least reduce the gap between the effects and the rest of the window.
I think 3 rows of target effects is max. iconsize normally 15 with 1 padding.
Maybe...
check1 (just set height to max)
check2=height<43 (do a check)
check3=height<31 (do a check)
height=check2 ? 31 : height (if less than 3 rows set to 2 rows, if not leave it alone)
height=check3 ? 16 : height (if less than 2 rows set to 1 rows, if not leave it alone)
Dunno.