Calculates of dropdown position lead to scrollbar flickering

[lexey111]

Hi,
we're using custom scrollable container and ui-select inside. It looks like calculateDropdownPos leads to flickering the scrollbar if position set to 'auto' and long select is placed at the bottom of form.

I did some quick search and change function a bit: except just dropdown[0].style.opacity = 0; ... dropdown[0].style.opacity = 1; I added dropdown[0].style.position = 'fixed'; ... dropdown[0].style.position = 'absolute'; to move dropdown out of page flow temporary.

It solves the problem. Unfortunately I can't make PR due to some reasons, but I think this is not very big change.

[user378230]

@lexey111 Can you use the issue template provided and provide plunkr and version numbers?

For reference: There was some attempt to fix something similar in #1557, #1123 & #1557 (comment) maybe it would be useful for your PR.

[Dexmaster]

http://plnkr.co/edit/FMUk3ZzrnDqpNJ3A9AUz here is a demo of a flicker.
The problem especially visible when we don't know direction +modal window or footer.

[Dexmaster]

Fix for situation when item goes out of viewport appears flicker before changing dropdown positioning. Here is fixing PR: #1936
Plunk of a fix: http://plnkr.co/edit/QxycwbMMYUpNoTLiubEg

[MatejQ]

We are seeing this same issue. Looking forward to a fix.