Probably you are looking at these sprites:
but the sprites with the changed width are located in:
I opened ComboBox.Forest.css
file with VS 2012 and was able to format it without JustCode by selecting all text and pressing Ctrl+K+C. I'm attaching the formatted file. If you provide us with a runnable sample reproducing the issue you had faced then I could modify your skin. In addition, could you provide us with a LiveURL demonstrating the issue?
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed