I tried to add some bitmaps to my start bar for controlling WinAmp. Unfortunately, WinStep does not seem to recognize hotspots in the reserved screen area. When I included some area above the reserved area, the hotspot then worked.

Is there any technical reason why hotspots cannot be in the reserved area?

Nope.

How did you add the hotspots?

I went to the HotSpot editor, added a hotspot, set it "Desktop". That enabled me to use the "Select Area" button. When I did that, it made my Startbar disappear, so I guessed where to draw the rectangle (my "play" icon disappeared with the startbar.)

I then tweaked the horizontal/vertical position (which were large numbers again since it treats my main monitor as X-pixels 1920 through 3839).

The hotspot did not work...it was a "Run Internal Command: WinAmp Play". I then changed the vertical position from 1160 (top of my reserved area) to 1120. Then clicking above my 40 pixel reserved area started the WinAmp player.

Do you feel the hotspot in the reserved area should have worked?

According to your description, and if I understood correctly, the problem is not the reserved screen space, but the fact that the target of the hotspot is the Desktop, when, in fact, it should be the NextSTART Startbar. How about using a Quick Launch hotspot for this?