Selection not getting dark

[Pelle Andersson]

Usually when I select something in the arranger area the selection gets darker/shaded and helps me see what's going to be selected.
But in my latest project that "function" isn't there any more!? My eyesight isn't 100% so it's quite helpful.
And the arragement doesn't slide over to the left when I reach the end of the arranger window at the right side.
I included a video of how it looks when it works. How do I get it back?
I've now also included the "not working" video!

Edited April 1 by Pelle Andersson

[David Baay]

Make sure the lower left button in the Select module (must be sized large to see them) to 'Select Events with Sections' is enabled.

Edited April 1 by David Baay

[sjoens]

That... and I don't see any "arranger" sections in the Arranger track.  Once you add one and select it, the affected track sections will get darker.

[Pelle Andersson]

Thanks for helping me out! When I got back after dinner after an hour or so, it worked again. Don't know what happened? A bug?
I've had this problem before but assumed I mistakenly hit a kbd shortcut, but it doesnt seem to be the problem?