improve last column resizing

[sgratzl]

closes #228

prerequisites:

• branch is up-to-date with the branch to be merged with, i.e. develop
• build is successful
• code is cleaned up and formatted
• tested with Firefox 52, Firefox 57+, Chrome 64+, MS Edge 16+

Summary

wip of a better resize experience

[thinkh]

Thanks for your draft. It looks already very promising and works well.

While testing I noticed that the scrollbar is jumping around after I stopped moving my mouse (while dragging) or released the mouse button. Why is that happening (i.e., what the is the reason for this behavior)? Can you point me to the implementation where this happens, maybe I can play a bit around and try to optimize it?

P.S. I saw in the code that there is a setTimeout with 1200 ms.

[sgratzl]

I tried to improve the behavior as good as its get. The columns size would still jump, cause it is too expensive to rerender all the time but I use a helper element that is used for a smoother experience.

[thinkh]

Thanks for the improvement. Now it works much smoother.

I would keep/merge it like this and come back if necessary.