Tor Taskbar button invokes non-Tor browser

OS: Windows 7. Steps to reproduce:

• Start your regular, non-secure browser. (In my case, this is Firefox.)
• Start Tor and wait for Vidalia and the TorBrowser window to open.
• Right-click the TorBrowser tile in the taskbar; this should pop up a menu with "TorBrowser", "Pin this program to taskbar", and "Close window" as choices.
• Select "TorBrowser" from this menu. Expected result: Either a new TorBrowser window should open, or the existing TorBrowser window should be brought to the foreground, probably with a new tab having been opened within it. Actual result: My (non-secure) Firefox window gets focus, and opens a new tab.