Small white horizontal line with a little triangle no longer disappears!?

[GhostlyFrend]

Please find a similar topic here (with a workaround):

Toolbar - Handle Bar - Flight Menu (triangle) will not disappear

v1.18.13 .0 My Flight Menu (triangle) will not disappear. Mouse over an open panel (like the map) and it does disappear, only to return when I move the mouse back over the main screen. I have reported this to the ZenDesk.