ALT-TAB doesn't switch Adobe Lightroom properly

Running Adobe Lightroom 2.5 64-bit under Windows 7 64-bit Home Premium, the Windows ALT-TAB task switcher doesn't function properly for Lightroom.

ALT-TAB pops up a list of running apps in thumbnails, and successive TAB keys while holding the ALT key will cycle through the list. Releasing the ALT key should perform three functions:

(1) Bring to the foreground the selected app
(2) Place the selected app first in line on the ALT-TAB list of processes
(3) Slide the entire list down in sequence, maintaining their relative position

If Lightroom 2.5 is running, it fails to slide down the list when another app is selected, but rather goes to the end of the list. This makes it impossible to switch successively between Lightroom and another app with repeated ALT-TAB commands.

Further details: happens whether desktop composition (aka Aero features) is enabled or not. Another symptom: upon selecting another app via ALT-TAB, Lightroom sometimes remains in the foreground.

Problem happens when running Nikon ViewNX and Adobe Lightroom concurrently, however the incorrect ALT-TAB behavior only affects Lightroom. Behavior continues even after shutting down ViewNX and restarting Lightroom.