The highlight option for the Win7/Modern style can be controlled by the registry key here :
HKEY_CURRENT_USER\SOFTWARE\Stardock\Start8\Start8.ini\Start8
Create a key of type REG_SZ and give it the name Highlight and assign it a value of 0. Then sign out and in again and the highlighting is disabled. If you had previously had Start10 installed this setting would have carried over to Start11.
I think this thread got missed as this question was answered elsewhere on the forums before but not in this thread. Sorry about that.