So, this is a strange occurrence, which seems similar to other questions but which I've not been able to find a reference for. Maybe my Google-Fu is not strong right now.
It seems to be a common complaint that user's root apps (sudo'd apps like Synaptic) are falling back on default themes. Usually the solution is given as "copy themes from
/root/.themes," for example. This hasn't worked for me, because there's nothing listed in
~/.themes for me.
Then I figured out that changing the controls setting in the Appearance dialog breaks root app theming instantly. See the following screenshots.
Installing another themeset (such as
grey-theme from Synaptic) appears to break this somehow too, although it goes away when uninstalled. I have not tested this extensively and it may be a fluke related to the controls changing.
On a hunch, I tried running
sudo mate-appearance-properties and/or
gksudo mate-appearance-properties. Notably, nothing changed when I selected different controls, not even the root app. Also,
sudo had only the default theme selected, but
gksudo had "Custom Theme" selected, which was identical to the default and also could not be changed. Unsure what this means, if anything.
So, long story short, I doubt this is a bug per se, but I would like to be able to change my default theme/controls and have root apps follow it somehow.