MacOS – Mouse not reacting to hover when bamboo tablet unplugged

I have a mid-2010 15" Macbook Pro with 10.8 installed, and I use a Wacom Bamboo tablet (one of the older ones, it's model MTE-450). I've noticed that whenever the tablet is plugged in, many hover states for the mouse no longer work for the trackpad and generic plug-in mice.

For example, normally if you hover over the three buttons at the top left of a window, they'll show a "x – o" pattern. However, if my tablet is plugged in, and I move the mouse over to hover, no hover occurs. This is the same with the dock icons, and with close-tab on Safari. Unplugging the tablet does nothing, and so far only a restart will fix this.

Any tips on how to start fixing?