Without this fix, a CPBoxOldStyle box with a CPBezelBorder would draw with the correct border colour and fill, but with an additional inner shadow, unlike Cocoa.
This fix makes it so that only primary and secondary boxes draw with the special "well"-like shadow style.
Without this fix, setting a corner radius of 0 on a CPBoxCustom resulted in there being a corner radius anyhow.
This fix makes sure to preserve the corner radius, border width and margins for non-primary style boxes.
In Chrome, a primary CPBox (showing the new recessed rounded corner look) had distorted and jagged edges in Chrome due to the clipping mask.
This fix places the clipping mask on integer coordinates which seems to resolve the problem.