Language dropdown cut short when open

[gjb2048]

Ref: https://moodle.org/mod/forum/discuss.php?d=266437#p1152778

There is a max-height on the open class.

[gjb2048]

Ok, related to moodle/moodle@ce65578 which is related to https://tracker.moodle.org/browse/MDL-41788 upon which the Essential theme implemented the workaround:

.open > .dropdown-menu {
overflow: visible;
}

Which now breaks the core fix.

[gjb2048]

Note: Core is fine as has YUI version of Bootstrap JS or is configured such that the menu's only drop down when clicked on. However, Essential uses jQuery and the drop downs work when hovered. So hence the disparity.