Adjustment brush Zooms

Hello everyone. I'm not the most tech savy guy, so struggling to figure out why my custom brush tool doesn't seem to be working properly in the camera raw filter mode.

Normally, I can select the brush, adjust the sliders, and then pan the brush wherever I want it to work. 

However, now I get this small square box and when I release the mouse button it zooms in. I can't access the brush.

I'm sure it's a simple fix, but I'm just not seeing it. Appreciate any help!