Transitory text highlighting in PDFViewCtrl

I tried overriding OnPaintBackground, but nothing drawn here is ever seen. I noticed in your example, you override this with an empty function. It is not clear to me why one would override in this way. Obviously I don't understand the relationship between the OnPaint and OnPaintBackground as it relates to PDFViewCtrl.

Right now we are merely using colored, non-filled rectangles, over the document, by overriding OnPaint to indicate numerous selection areas our custom utility uses for different purposes. Solid areas, of course, will occlude the text within the area we are attempting to highlight.

What would be a huge help is to be able to paint color coded filled rectangles UNDER the text and graphics of the page to provide visualization of these areas. Is this possible?
Lee Gillie, CCP
Online Data Processing, Inc.