Hi,
I believe it's the overflow="scroll"; and maybe a timing issue. I've reported it if it's something fixable. That space on the right is the place for the scroll bar, it's as if when it first opens it has the space available while it looks to see if it needs the scroll bar, but after it's closed and then reopened it knows it doesn't need the bar.
I cannot get my cache cleared..grrrrr....I have no clue where the page is being hidden on the computer

outside temp internet and temp files, so I can't test to see if it does that if you mouseover the Company item first or if it only does it in the ones you mentioned. And, I can't play around to see if there is something else in those first two submenus that is interacting with the overflow="scroll"; i.e. an arrow, that is causing it.
Ruth