Safari 6 gets stuck; won't scroll or scrolls to show blank area
I've been having trouble with Safari 6 since upgrading to Mountain Lion several days ago. The symptom is that after using Safari for a while, I'll go to a Web site and the page will load, but it won't scroll. Sometimes when that happens I can't click on links or controls either. Other times, the page does scroll, but rather than show the rest of the page, Safari shows empty space of the page's background color. Refreshing the page doesn't help, nor does closing the window and visiting the URL again, but if I open a new tab or window and go to some completely different site, that page usually works okay. Once a site gets "stuck", I have to quit and restart Safari to get it to scroll again.
I've disabled all extensions and the problem still occurs. It's erratic, though, and seems to happen more frequently on some sites (metafilter.com) than others (cnn.com). It sometimes seems that opening a set of tabs (with "Open in Tabs") makes it more likely to happen.
I am working on a Web development project now, and am using Safari's JavaScript debugger and Web inspector frequently, if that might have something to do with it.
This is driving me nuts. It's disruptive to my development workflow, and I'd hate to have to turn to Chrome or Firefox for the work. Can anyone suggest some diagnostic tricks to try to figure out what's going on -- or, better yet, a solution?
Thanks!