Is there an automatic, non-focused refresh of the desktop?

Is it just Digsby that causes a refresh upset, or does BumpTop not refresh the screen until it gains focus? Digsby's pop-ups fade away slowly, and if I don't click on the desktop, then it doesn't fill in the now black areas. Not sure how this would affect or be affected by file deletion/addition/modification on the desktop without focus. Perhaps something worth investigating (not sure what the solution would be)