Here are my few cents:
Some programs / tasks should be able to use the whole screen, and not bee affected by DesktopCoral. Maybe make a list like in Prosess Tamer?
The opacity is really confusing. I would suggest to remove the ability to have a background-option in DesktopCoral, and rather have a "switch" ON/OFF for making it invisible.
Option of having a taskbaricon or not. it would be nce to just open main exe again to get the prefs-window. But this isnt half as important to me as 1 & 2.