Added vendor prefixed to class set when modal is anchored to menu element.
Added vendor prefixed to class set when modal is anchored to menu element.

ttiurani/extendedmind,ttiurani/extendedmind,extendedmind/extendedmind,extendedmind/extendedmind,extendedmind/extendedmind,ttiurani/extendedmind,extendedmind/extendedmind,extendedmind/extendedmind,ttiurani/extendedmind,extendedmind/extendedmind,ttiurani/extendedmind,ttiurani/extendedmind,extendedmind/extendedmind