Track display after combining regions

Ardour 8.2 and 8.4, Debian Buster

I am trying to combine two regions the regular way: selecting them, then selecting “combine”:

After the operation, the regions are combined but are displayed like this:

grafik

Sound is correct but I cannot see the recording anymore. I just switched to Ardour 8 and never noticed this before. Is it a problem or a change/feature I have missed?

Same behavior in 8.6.0.
Before combine:

After combine:

The track is still playing as expected but the wave graph isn’t displayed. Maybe I am missing something obvious but this is very annoying and I just can’t get around it. Any help would be greatly appreciated.