Graphic Glitches / White screens

[headcrash]

I know the current Windows client may not be supported for use with Windows 7, but I'm attempting it anyway. If I've made the mistake of missing a download for a Win7 64-bit client download please point me in the direction of it. Anyway, while using the current Zimbra desktop client I'm seeing a lot of display issues where clicking on a new tab will not refresh the screen (if you select text by dragging over the entire window you can read some of it at least). At other times the entire screen will go white and be unusable until I kill the process and start the client again. Both issues seem to be random and intermittant, as I've gone up to 3 hours without seeing either of them. If anyone knows any tricks or has anything to try please let me know.