Opening a tab in a zone with more tabs than fit appended it past the right
edge of the scrolling strip — the new tab and the "+" that created it were
both off-screen, so a second new tab meant scrolling back by hand. Activating
a tab from a keybind had the same problem in the other direction.
The zone header now scrolls its active tab into view on activation, and
scrolls all the way to the end when that tab is the last one so the trailing
"+" comes with it.
Brooklyn Nicholson
dfe3a23a60