The HTML of the new filter bar looks like this:
<div id="filter-bar"> <div class="tag-filter"> ... </div> <div class="filter-bar-links"> ... </div> <div class="layout-settings"> ... </div> </div>
filter-bar-links have height 38px. The containing div
filter-bar is also given height 38px but this includes 1px bottom-border. So the height available for its contents is only 37px. As a result, the inner divs protrude vertically out of their container, potentially messing up the layout of other elements.
This does not happen yet because there is still enough horizontal room in the layout. But once the interface is localized to a language with longer tab names, there may be a surprise:
(Tab renamed with Chrome dev tools).