It would be great if "cu_deffcc.png" allowed for the use of the tranparent color, so that you could make the icon underlying the actively selected combat icon something other than a square block (like a circle, a shade under the active character, an arrow pointing at it etc.).
For developers:
The image being talked about is the combat cursor. Transparency could be like sprites or icons, with pixel 0,0 determining the transparent color.