Transparent Slider Control

I found a Slider control on Planet-Source-Code....i modify ....and try to use.
..but I have a little problem....when i set Transparent=true the control not repaint smooth....

Any Help please...!

Have you posted feedback on that site? Maybe the author will be interested in a potential bug and reply to your question.

Thank you ....LaVolpe for quick answer....(and by the way I appreciate your work....CONGRATULATION for all you have over the years)
I do not post feedback....it is an old control ...and problem is only when Transparent=True (background transparent) and this properties is add by myself...
Original control have only backcolor