Hello Klaus,
I've just began to use Combobox plugin to display a list of available scenes in mobile versions of my virtual tours and I noticed an issue I want to report to you.
In my current project I have a huge scene list and some of them are hidden down below the shown ones, so, users have to manually scroll down to get them. My fear is that in some cases, as many of my users ain't that familiar with this feature, they may think that the displayed ones are the only ones available and not drag the list to see the hidden ones.
As I see from the Combobox plugin description https://krpano.com/plugins/combobox/#top there is a scrollbar or something similar into desktop flash version of the plugin, but in the JS version there is none available as far as I see.
My proposed solution to this issue is very simple, maybe if you add a small white/black to transparent gradient at the top and bottom of the list, that may work as a clue for users to see that there are more scenes hidden up/below. That's basically how iOS manages this same option and because of that is a more universal way of doing it. I've already tried to implement this by customizing the image plugin but it doesn't works as plugin's image is below the text layer in the plugin and transparency doesn't cover it.
Is just a suggestion and hope it works.
Best regards
Luis