Windows 7 Onscreen Keyboard Keeps Popping Up?

I have the icon pinned to my taskbar, and normally the way I use it is I click on the icon in the taskbar when I want the osk to pop up so that I can use it. When I'm finished with it, I click on the minimize button and it returns to its spot in the status bar and stays there until I click on it again. Now, *normally* when I pass my mouse pointer over the icon, just a thumbnail of the osk will appear. But lately when my mouse pointer simply passes over the icon, the osk will pop up and appear on my screen in full size, and I need to minimize it to put it back onto the taskbar. This is very inconvenient because every time I bring my mouse pointer down to the status bar to choose an icon, I inadvertently pass over the osk icon with my mouse pointer which causes it to pop up.