Tested on 21013-05-16 using latest nightly built from http://hg.mozilla.org/mozilla-central/rev/cc139752bed4 While testing 831913 I noticed that if you bring up the settings flyout by typing Start-c while Metro Firefox is in snapped view, the Settings flyout is empty. It's a little unclear if that flyout belongs to the empty area or to Metro Firefox. Steps: 1. Open Metro Firefox and put it in snapped view 2. Swipe left or Start-c to bring up the Charms 3. Select the Settings Expected: Maybe I should see the Metro Firefox options(?). Actual: An empty Settings flyout.

This is regular win8 odd behavior. The charms seem to always apply to the largest snapped app. If there is no app running on the larger window it shows blank settings.

MS says this shouldn't be allowed, and isnt really sensible, as the flyout is often wider than the snapped width. We shouldn't let users get here.

Comment 1 is correct - the charms always apply to the larger ("filled") app if there is one. When there is no filled app, the charm panels are just empty. This is perhaps a bug in Windows. In any case, it affects all Metro apps equally and is outside of our control.