I was flying through my work-flow and my fingers got tangled up... I hit a key combo somehow and the behavior of applying things to the currently focused image in a group selected images changed.
Previously, if I had 5 images selected and wanted to reject just the one that I had focus on, hitting X would reject just that one.
Now, it's rejected all selected images.
This is really slowing down my workflow so how do I revert that behavior so that actions such as reject apply to only one photo out of a group of selected photos?
The answer to this is that Auto-Sync was on. Turn it off and the behavior reverts. (http://www.lightroomforums.net/showthread.php?13307-how-do-I-turn-off-auto-sync)
[Y]ou can use the menu bar: in Library go to Metadata menu and uncheck Enable Auto-Sync. In Develop, the Enable Auto-Sync option is in the Settings menu.