New gtk-vnc slower?

I have a collection of virtual machines that I use to test cross-platform compatibility of some code I'm developing. Today, the virtual machine I was working on kept getting slower and slower whenever a window refresh was needed. It got to the point that refreshing a terminal window was taking nearly half a second per line. My eyes could easily track the refresh going on. Moving a window was impossible, as I could see the entire window being redrawn, pixel by pixel, and it would just keep going long after I had released the mouse. Keys were repeating right and left, probably because of a sequence like <KeyDown, refresh action that takes a really long time, KeyUp>. I shut everything down, logged out, and even rebooted, to see if it was some weird behavior caused by a recent update that had only partly taken effect. When I started my VM back up, it was very snappy. But then, over time, it got a little slower and a little slower, until eventually I was back to watching refreshes happen line by line again. This never happened before today. I looked through the recent updates my machine has received. All I can see that might be relevant was an update to gtk-vnc-0.4.2-1.fc14.x86_64. The machine in question is a quad-core Intel with 8GB of RAM and an Nvidia video card of some kind. (Sorry, should have checked which one before leaving work.) The host is fine; it's just the virtual machines I open with virt-manager that are affected. I tried several, and they're all behaving like this today, which argues for the problem being on the host side. Is anybody else seeing this? Is there any other component besides gtk-vnc that I should examine as a possible source of the slowdown? Thanks, -- Jerry James http://www.jamezone.org/