Application menu dropdowns right-aligned in Windows 7

I've noticed in two of my Windows 7 installs (both 64-bit) that after the last couple of updates, most application menus seem to be right-aligned instead of left as if there's not enough room to display it left-aligned (the window is 1600px wide, so plenty of room there).

Any thoughts as to how to switch this back to the default? Pretty much every application is affected – Adobe CS4, VS2010, Notepad.

1. Press the Windows logo key+R to bring up the Run dialog box. In the Open line, copy/paste the following line of text.

   shell:::{80F3F1D5-FECA-45F3-BC32-752C152E456E}
   

2. Press OK.

   This will start the Tablet PC Settings configuration dialog (Even if you do not have a Tablet PC).

3. Select the Other Tab.

4. In the Handedness section, place a check mark in the Left Handed option.

5. Click OK.

Remember to restart Explorer after doing this.