Probably a bug - Scroll down jams while customizing

Hi Tom, I'm a non-techie building my personal blog site with the help of your theme & add-on, both of them are too good.

I've observed that while I'm customizing the site, on the left hand side there is a panel (set front page, site identity, layout etc.) and on the right hand side live preview of the site. During customization, the scrolling on the right hand side gets jammed sometimes. I've to choose tablet or mobile view to bring back scrolling and then scrolling works fine in desktop mode.