We already apply computed top margin to notification popup and
permission popup so that they are visible. But it seems that if the
panel is close enough to screen bottom edge (such as in maximized
windows) then the panel contents fail typically fail to render. For
whatever reason, changing the default margin for
customizationui-widget-panel makes the failures much less frequent
although it doesn't appear to get rid of the issue completely.
At least on linux permissions-popup and notification-popup panels
don't get side=bottom attribute so the open downwards which causes them to
be drawn outside of screen. Fixes#493
Because the toolbox has display: contents, we need to display the background
separately for each toolbars. In addtion, on linux the main-window has
transparent background-color so we need to set toolbar opacity to 1 to
prevent transparent window areas.
When urlbar is open the panel input-container height changes based on
whether or not go-button is shown. Add a pseudo-element at the end which
has uses the same height value as go-button would.
In addition, this patch adds a pref
userchrome.toolbars-below-content.tabs-at-bottom.enabled that can be
used to make tabs as the bottom-most toolbar.
