2.8 Disappearing Workspace Tabs?

It had been a few weeks since I downloaded the latest 2.8 build when I did this morning (March 12, 14:38:10 - 936014ea8c74) – now some of the Workspaces (UV Editing, Shading, Rendering, Compositing, & Scripting) no longer have the Workspaces bar. I can still change workspace using Ctrl-PageUp/PageDown, but I can’t make the WS tabs show again in those workspaces. There’s a tiny tab with a carot symbol that looks like it should be doing that, but clicking it does nothing.

Is there a way to make the WS tab bar show up on those workspaces, or is this something the devs are gonna fix in an upcoming build?