dda3e121a8
Something about the arrow positioning logic causes background windows to raise. The tab preview was only made an arrow panel because other panels consume wheel events[1] meaning we couldn't detect them to close the panel but it turns out there is a dedicated `rolluponmousewheel` attribute that allows us to automatically close the panel anyway so this removes the dedicated wheel handling and adds the correct attribute. The original test added for closing on wheel events wasn't actually working as it wasn't actually dispatching any wheel events, the panel was closing for other reasons. This switches to sending native mouse wheel events. [1] https://searchfox.org/mozilla-central/rev/098f910d0593b12a42089dd8f40dcd19d1121430/layout/xul/nsXULPopupManager.cpp#546-557 Differential Revision: https://phabricator.services.mozilla.com/D202709