Please read the original post more carefully, I have taken care to describe it accurately and succinctly. The link is provided in a private reply directly after the OP.
You noted in your screenshot that the onclick highlight (the blue box, or red box, or red dashed line that occurs around a clicked menu item) is different in different browsers, it is also different on different buttons in the menu. It should be consistent, and should not have any highlight at all on a click. Just like in the standard menu operation within X theme.