Style sheets usage from the lucid grid vs as-launched from related displays

[klauer]

Loading up the BTPS screen from las (${EPICS_SETUP}/lucid-launcher.sh LAS), and popping it out results in this awful looking display:

Whereas the configuration editor loads up without the typhos stylesheet via the PyDM related display widget, which looks roughly as it was designed:

Not sure of a really appropriate fix here, but some reactionary thoughts follow:

• The typhos stylesheet remains ugly
• Maybe an opt-out mechanism for the typhos stylesheet somehow?

[ZLLentz]

I saw some other wonky stylesheet behaviors today that I can't explain. The chemrixs vacuum screen does not open (or doesn't use?) the stylesheets correctly when opened as a related display from lucid specifically, but it works from from lucid as a shell script and it works fine outside of lucid as a related display. I don't know if this is related at all but the title seemed to match... I have so far be unable to understand what exactly is wrong here.

[ZLLentz]

I don't think lucid ever calls pydm's stylesheet mechanisms
https://github.com/slaclab/pydm/search?q=apply_stylesheet
https://github.com/pcdshub/lucid/search?q=pydm

[ZLLentz]

PyDMRelatedDisplayButton is opening a window with no parent that can only inherit a stylesheet from the QApplication, which gets set up with a stylesheet courtesy of typhos.use_stylesheet
https://github.com/slaclab/pydm/blob/dc0346004fa15d13ddfe198f21f62bbdf585b715/pydm/widgets/related_display_button.py#L464

lucid/lucid/launcher.py

Line 193 in 3b53413

typhos.use_stylesheet(dark=dark)

https://github.com/pcdshub/typhos/blob/76486e30b16daf81df3e475ada978affa1ef68a1/typhos/utils.py#L232
https://github.com/pcdshub/typhos/blob/76486e30b16daf81df3e475ada978affa1ef68a1/typhos/ui/style.qss

[ZLLentz]

First stab at this here, but I ran into some conceptual roadblocks: slaclab/pydm#950