I found something that one might consider a bug though it's just aesthetics. Mac client 0.91.99.9 running on 10.9.4.
When I start the client, the wallet list is fine:

If I click on a wallet in the list, however, to perhaps just select it or double click for more functionality, the title bar of the list turns blue and it doesn't change back unless I quit and restart the client. Also, if I'm allowed to be particularly anal, there's a small line / bar on the left side of that box list that, if it were in Excel, would suggest that there's a collapsed / shrunk column. It in no way affects functionality as far as I can tell but I figured you may want to know.
