In sync edit mode, when scrolling, the scroll bar appear on the right and it's in the right place.
But when you move the cursor to the far right of the window, the bigger, clickable scroll window appears and it covers half of the CR tick boxes. So if you want to quickly scroll and add/remove CR, you either have to wait until the scroll window disappears or try to "target" the left side of the tick box if you don't want to click the scroll window and end up somewhere else :)
I cannot figure out why this larger scroll bar appears...
I will enlarge the CR column on next version. In the meanwhile, you can change your system setting to avoid this problem: