Is it possible to extend the "IGButtonColumnManager" class (extra sample for iGrid.Net) so that the background color and foreground color can be changed to desired colors?
Many thanks in advance!
That helper class is based on the ButtonRenderer  class from .NET Framework. We call its DrawButton  method to draw the push button inside iGrid cells. The functionality of the ButtonRenderer class is a wrapper for the Windows API calls that render push buttons using the current visual style of the OS. This may depend on the version of Windows, but in the general case you can't change the button image because it comes as a bitmap from the system styles.

To implement what you need, the whole drawing approach must be changed. Obviously, we need to rewrite the drawing of push buttons with the hover and pressed effect from scratch. But this will complicate the sample a lot and we will also lose the system look of the cell buttons.