Created attachment 73980 [details]
Unpack and open the HTML file

when you move upper class down, diagram top border moved with the class down, and all other classes on the diagram moves
up relatively to your class(the same from left), at the same time 0-0 point is always on scene. this cause this funny
effects, but it's not a defect or not a p2 anyway, even if there is better behavior possible.

all I said was about "this behaviour is expected" but feel free to reopen if you are dissatisfied with such behavior,
but may be it will be enhancement in this case.

Thanks for explaining, Sergey!

This all sounds reasonable. Why does this approach result in this "funny" behavior.

The core issue is that the diagram element that is being moved stays at its location (at least most of the time) while
the environment around it is moving. This is counter-intuitive. The visual cue that the element I am dragging around is
moving relative to the ground below it is missing. It is like sitting in train watching another train passing by. 

1. If I move the class in the top-left corner to the left or upwards, the current behavior is ok.
2. If I move it to the right or downwards the class has to move away from the left or top border towards the other class
and the canvas has to stay where it is.
3. Only if I move the class beyond the bottom or rightmost border the canvas may start moving again.

The current implementation violates 2) and 3) and this is a serious flaw.

Regards,
Georg

yea, I don't like this behavior too, but it's a kind of "visible usability issue" and do not broke any functionality, so
p3 or enhancement as many usability requests. also is dependent of issue 105496.