For admin, we can drag that button:
For regular users, it disappears and the panel shape is fixed:
Looks fine for new topic. New topic and reply look fine in safari.
Looks fine when developer toolbar is opened.
Quite peculiar... is the text always blurry?
Yes, In chrome on Mac when I hit reply. Works fine for new topic.
I think this is a bug in chrome. In pretty sure it's caused by a transform css property and can be fixed with forcing 3d.