I upgraded my Galaxy S III to Android 4.0.4 last night and now I can't drag apps to the taskbar anymore.
Is there a setting I can change to be able to drag apps to taskbar again?
According to the User's Manual, there isn't a setting that locks the Primary Shortcuts. So I would suggest turning the phone off and then restarting it.
Here are the instructions from the User's Manual for Adding and Removing Primary Shortcuts. Perhaps there's a step here that you've missed.
This question is protected to prevent "thanks!", "me too!", or spam answers by new users. To answer it, you must have earned at least 10 reputation on this site.