[xubuntu] 16.04 - XFCE, but using Dolphin, edit filetype problem - what am I missing?

Hello everyone.

I'm currently setting up a new computer with Xubuntu 16.04 but I've been using Dolphin for years and like it too much to part with it. Works like a charm under 14.04, but have some issues under 16.04. some are easily fixed, others I caot find what is missing.

I know that XFCE doesn't have every bits & pieces to have dolphin working 200%, but I don't personally like KDE itself enough to use it daily. I don't really care what I have to install to get those bits & pieces working as space isn't a issue.

The worst problem I have is that I can't edit filetypes - when clicking on deal-breaker on a new system because I hate the defaults.

When I right click on a file and select Properties, then File Type Options, nothing happens. the "Edit File Type" window doesn't appear. I've been trying to find out what piece I'm missing, what do I need to install/configure to get this working but I caot find anything about this kind of issue, nor anybody else with it. The only thing I haven't tried is to install KDE completely but still use XFCE as I see this pretty much as the nuclear option.

Anybody got an idea?