I'm not getting any reports from other Steam users about menus not appearing, so I'm not entirely sure that it's a Steam issue.
Just to be clear, you are hovering your mouse over menus and they are disappearing (as shown in the video), correct?
On a side note, if you are trying to open a screen and nothing is happening (except for maybe some beeping), it is possible that the screen is opening up in a position where Windows thinks a monitor is still operating. If this is the case, try right-clicking on the VA icon in task bar and then select, 'Relocate to Primary Display'. See if that helps.