Selecting too many categories error limit display message

When you set a limit for how many category's can be ticked at once and get shown an error message in a red quote block. It says this after I set the limit to 2 only and ticked 3 cats to see if stopped.

You have selected too many categories. You may select up to {@GALLERY_IMAGE_MAX_CATEGORIES} {if GALLERY_IMAGE_MAX_CATEGORIES == 1}category{else}categories{/if}.