I searched high and low (maybe I have not searched enough) but I cannot find a good solution for creating a control that can have transparent background. So I did some experiments, incorporated some of the ideas I happen to stumble on the net and at last I was able to create a user control that can have a transparent background. Cool! I updated my Code Project article to incorporate the transparency support.
If you want to check it out, click here. I welcome all comments specially when the rating that was given was low, because I want to know how else can I improve my solution.