You need to make the window slightly taller.

The Store will vertically scroll if it decides there isn't enough vertical space.

i assume in most cases that height is 768 pixels. since thats the lowest resolution its supposed to support.

Also why does 1 option set minimum height, and the other set width AND height. shouldn't the other only set width, to eliminate redundancy, and allow for more options? also its a little less confusing that way ,

Is there a hotkey you can hold to make the scroll wheel scroll horizontal, even if it could scroll vertical. (if not you should add one, it would be a nice feature)