Scrolling on marker click

I have the sterling theme installed and with it activated, if I click on a marker link to get the box pops up but has scrolling on it. If I activate a default them it is ok. I contacted the developers at sterling and said they could not figure it out. Any idea why this is happening or what I should modify?

https://ww.wp.xz.cn/plugins/wp-google-map-plugin/