Photoshop :: CS4 Window Stays In Background

When I drag an image file into Photoshop CS4, the file opens but Photoshop remains in the background – i.e., in the window behind the one that I dragged the file from. For example - I open Photoshop, then open Bridge, with the Bridge window mostly covering Photoshop’s window. Drag a file from Bridge to PS. The file opens in PS, but the PS window is still behind Bridge’s window. I have to either ALT-Tab or click on the PS Window to bring it to the front. On prior editions of PS, it would come to the front automatically when a new file was opened. I still have CS3 on my computer, and verified this. This happens whether the file is dragged from Bridge, Windows Explorer, or Thumbs Plus. It happens in both the 64 and 32 bit versions of CS4. I looked through the preferences and don’t see anything that seems to relate to this behavior. Is this how CS4 is meant to work? Is there any setting I can tweak to change this?