The new Window Layouts tool has UI flaws observed in the latest nightly Linux appimage (2d068df) and the Windows nightly (g82a8db752) builds. If a new layout is saved (using the Choose Workspace tool) it does not appear in the quick access drop down list until after a restart. However, it is available in the listings of the Choose Workspace tool. At the start, the Windows Layouts quick access drop down list shows the first (in alphabetical order) name of the saved layouts, regardless of the actual layout in use. After a layout is selected, it then displays the selected layout name. These are minor presentation flaws but could confuse a new user.
Can you take a look, Jouni?
The quick drop down was part of a UI experiment. It was never actually meant to land into the master branch, but got pulled in with other changes. I have now removed it.