I just tried it again, and it seemed to work all right on IE as well as on all other browsers. I even tried a different computer, and a virtual machine, all work just fine:
1. I clicked the Ajax Search Pro menu, then created a new search instance called “Test”: https://i.imgur.com/gjgJBbr.png
2. Then after clicking the “gear” icon I am taken to the search settings, where the highlighter feature is visible as well: https://i.imgur.com/VADGgTJ.png
