Is it just me or has anyone else found this with the Sitefinity 5.1. When you drag the margin of a content block to make the edit area a bit wider, it sticks to the mouse and you sometimes have to click around frantically to drop the margin. If you click in the edit area then it drops it ok. With my custom backend template, it really does not unstick from the mouse that easily. Sometimes you have to double-click around to drop the margin.
I guess it would be helpful for Telerik if you specified in what browser on what OS this is happening and if reproducable every time.
It was only an exploratory question so far, just to see if anyone else has seen something like that. It happens in both IE9 and FF. It used to only follow the mouse if you held on to it. Now though, if you let go of the mouse button then it follows your mouse. Especially if you expand outwards first. Strange resizing behaviour.