Unfortunately, the 7G version introduced a bug here. While I never did duplicate the "frozen fish" bug, I downloaded and tried the latest beta this morning and immediately ran into a screen refresh problem. When switching from full screen to windowed (via the F key), the desktop backgrounds on the non-main screens are not refreshed. In fact, even parts of open applications are not (though other parts strangely enough are). I'll pop a screencap here:
http://webpages.charter.net/rlsimon/screencap.jpg
I'm running a 3 screen setup with an ATI 9550 driving the center (#1) and righthand (#2) screens and an NVida FX5200 driving the lefthand (#3) monitor. In full screen mode (or windowed mode as long as the window does NOT cross onto another monitor) I get decent frame rates in the 33-35fps range. Any time any part of the window is displayed in either the lefthand or righthand screens (#2 or #3), the frame rates drop to ~5fps. This includes if I shrink the window down and move it so that it is entirely within the #2 or #3 monitor. I only get full frame rates when the window is completely enclosed within the #1 (center) monitor. Here's another screencap showing that:
http://webpages.charter.net/rlsimon/screencap2.jpg
You can note by the Netstat util running in the LR corner that the problem doesn't appear to be one of running out of CPU cycles. While the CPU usage spikes during the initial startup and switch-over to windowed mode, it then drops well down to within normal ranges.
Let me know if there's any other info I can provide to help track this one down.