Problems with windows, title bars, and panel in Unity

I've been running Ubuntu 12.04 Beta 2 64-bit for about a week, and in the last couple days the title bars on some of the windows are not clickable. The title bars do appear, but if you click on them, the window itself becomes de-selected (as if you clicked on whatever was directly behind the title bar). As a result, it is not possible to close, minimize, maximize, or drag the window via the title bar. This can happen with any application, and it seems to occur intermittently (though once it happens to a given window, that window will continue to have the problem unless the application is closed and restarted).

Also, occasionally, when I open a window, the entire content area is blank/white (the title bar is still visible). Typically if I simply minimize and then re-open the window, the content will come back.

Finally, I'm using SpiderOak backup, which has been added to the Unity system panel whitelist, so its icon appears in the panel. When I start up, the icon is there, but at some point it eventually disappears, even though the background process is still running. Oddly, if I click on the Dash Home button, when the panel is covered by the purple overlay, I can vaguely see the SpiderOak icon through the purple overlay -- but when Dash is closed, it disappears again.

Any ideas what could be causing these problems and how to fix them? Thanks.