Step to repodice:

Open the firefox.
Select text on address bar directly without focus it first

What actually happened:

The megabar shown, and text select area is no longer under your mouse.

What do you expect:

Megabar shouldn't show unless you click keyboard (like what chrome did, just focus won't trigger it to pop out, you must click keyboard)

And

The font size of initial state should be identical to megaBar state so it does not looks off even you decide to type after select.