Bottom tab border issue with 0.17.0

[Strykar]

After updating today, when I create a new tab, I see a gray bar at the bottom where additional tabs would be shown.

It used to be black before and I would like to keep that look, instead of a visible horizontal bottom bar.

I looked at the changelog and I'm unsure if :opt: background_image needs to be set here now to show a blank/black bottom bar?

Relevant tab config:

bell_on_tab             yes
tab_bar_edge            bottom
tab_title_template      {index}: {title}
focus_follows_mouse     yes
active_tab_foreground   #000
active_tab_background   #73D216
active_tab_font_style   bold-italic
inactive_tab_foreground #444
inactive_tab_background #999
inactive_tab_font_style normal