v8.1.0
I’ve noticed in general that the performance of Perspective in the Designer is a bit sluggish to do things, and this bug may be a result of that.
When I click and drag the mouse to select components, I have to click-pause-then-drag otherwise the drag starts mid-way through, as in the screen capture:
I notice this only happens if have a lot of object in your view.
Your case even worse if objects are embedded view.
I know we've both said this before, but I find it concerning that nesting Views only a few levels deep is an issue.. If it's 6,7 or more levels deep, that's understandable, but certainly not 1-3 levels deep. This should be an expected situation 
In that example, I have I think 2-3 layers of nested Views.
But I see this even in root container if I have so many object.
In nutshell the perspective performance in design and runtime is not good and cause we spend a lot of time for develop. Even now I see black screen or timeout error time to time. I hope they fix the performance problem soon and make it like vision speedy.