Disabled Hotkeys still performing actions

I'm trying to remove the hotkeys (Keyboard Shortcuts > Tools) for Increase/Decrease Brush Size/Hardness and Next/Previous Brush. Even though I've deleted these shortcuts, pressing these keys still perform their respective actions. Even after explicitly assigning them to different keys, the square brackets, comma and period keys still perform these default brush operations I'm trying to prevent. Does anyone else experience this unwanted behavior, and is there a way to resolve it?

I'm using Photoshop CS5 64-bit on WIndows 7.