fix dropups and add positioning

[pkozlowski-opensource]

dropdowns are not dropping up with Bootstrap 4.beta. The fix is not trivial as we need to use the positioning service.

[achimha]

Is there any workaround for the time being?

[bgaillard]

Hi, as @achimha we also need to quickly fix this, is their a simple workaround ?

[pkozlowski-opensource]

@achimha @bgaillard I'm not aware of any work-around but we are going to release a patch (beta.2) this week with a fix. If you really need it urgently please consider sending a PR. Thnx!

[bgaillard]

Hi @pkozlowski-opensource, releasing a patch this week would be perfect for us.

Thanks a lot for your reactivity !

[pkozlowski-opensource]

@achimha @bgaillard please review #1752 if you want to see it fixed faster :-)

[bgaillard]

Hi @pkozlowski-opensource, thanks a lot for this PR.

After testing I'm think I do not encounter the same bug as @achimha.

In my case the problem is that the Dropdown is placed outside the screen. I initially though the bug was the same because #1748 was marked as a duplicate of this case and was is positioning problems.

The following screenshots shows the problem I currently encounter with beta.1 version at left (the dropdown is placed outside the screen).

At right this is a screenshot of what I had with the last alpha version (this is the expected behavior).

On those screenshots the border of my screen is at right of the "grey scroll bar".

Do you know if its an ng-bootstrap bug or a Twitter Bootstrap 4 bug ?

I'm in holidays tonight so i do not have any time to test if this bug comes from Twitter Bootstrap or ng-bootstrap. During my holidays my co-worker @simonbaudry will be able to respond you I he has not too much work :).

[achimha]

@bgaillard that's exactly the problem I'm seeing, dropdown-menu-right doesn't work with beta 1 because Bootstrap 4 switched to a Javascript positioning service.

[pkozlowski-opensource]

dropdown-menu-right doesn't work with beta 1 because Bootstrap 4 switched to a Javascript positioning service.

Exactly. Since Bootstrap moved away from CSS and switched to JS we need to do the same. The first step is to use JS to position things and this is what #1752 does. #1752 will restore dropups but won't help with cropping and auto-positioning - this will be handled in #1171 (but in order to make it work we need to beef up our positioning service).

[bgaillard]

Hi, thanks for your work on this, my co-worker @simonbaudry fixed our problems thanks to your comments and other issues linked to it.