My problem was that hiking trails were not being shown on the maps on my tablet.
As it turned out (and as I suspected) this was caused by a wrong theme.
The map I was using was from Freizeitkarte
The theme that was being used was not suited for my map.
I tried to load a theme from Freizeitkarte.
But this theme was not being shown as something I could choose.
The only theme that was available was the internal 'Hike and Bike' theme.
I just looked at the available themes again.
Now all the internal and external themes are being shown.
I selected the theme 'Freizeitkarte fzk-outdoor-soft-v5'
The tracks are being shown.
My problem is solved.
I also see that I made a mistake when posting my problem.
I used the term 'track'.
This was incorrect.
I should have used 'hiking trail' or ' hiking path'
But it still is weird why it took so long for the internal external themes to become available.
As it turned out (and as I suspected) this was caused by a wrong theme.
The map I was using was from Freizeitkarte
The theme that was being used was not suited for my map.
I tried to load a theme from Freizeitkarte.
But this theme was not being shown as something I could choose.
The only theme that was available was the internal 'Hike and Bike' theme.
I just looked at the available themes again.
Now all the internal and external themes are being shown.
I selected the theme 'Freizeitkarte fzk-outdoor-soft-v5'
The tracks are being shown.
My problem is solved.
I also see that I made a mistake when posting my problem.
I used the term 'track'.
This was incorrect.
I should have used 'hiking trail' or ' hiking path'
But it still is weird why it took so long for the internal external themes to become available.