Uncaught RangeError: Maximum call stack size exceeded error when plugin is activated. Does not occur with the lite version of the plugin. Have tested the same plugin on a different site and is working correctly.
It was a prototype definition issue with the scrollbar plugin + a syntax highlighter script that is included in the theme. I have disabled the problematic code section within the scrollbar script, now it should be fine.
We will do a few more tests before making sure to include this in the upcoming release, as I am not sure which script exactly triggered the error.
Just make sure to have a copy of the wp-content/plugins/ajax-search-pro/ directory, and override it on your local environment as well. To have the change in effect, make sure to change this option as well: https://i.imgur.com/lBRDjAD.png