Idea for new Display Manager

["Whitney R. Armstrong" <warmstrong@anl.gov>]

Hello,

My recent experience with display managers left me with the conclusion 
that a new DM is desperately needed. Here is a quick recap of my 
experiences and thoughts dealing with the different display managers.
Note I am using the latest Ubuntu and Epics base-7 and my comments are 
tongue-in-cheek.

1. MEDM : It works! This old gem works (almost) perfectly. It has a very 
easy to use interface, but of course, is rather limited.

2. edm : Where do I download it? The webpage is broken. (Last 
documentation update was in 2007: is also not a good sign.) 

3. caQtDM: A home rolled build system is never a good sign. It compiles 
but then crashes when launched. I get a horrible hand cramp trying to 
debug things because who types "caQtDM" with ease? Does it work... I 
don't know... maybe?

4. CS-studios: First I follow the instructions on the website: fails.  
Eclipse cannot install all the needed parts. Next I try running maven to 
build from the core directory. After maven downloads the entire internet 
the build fails with some horrible java errors. (Why is java still a
thing?)  CSS looks nice from all the pictures but it has some bugs (or 
undocumented features).

Anyway, if I missed any DMs please let me know. As you can tell,  IMO 
MEDM is still the winner.

The idea for a new display manager is to use an "immediate mode" gui 
(imgui) design  which is much easier than "retain mode" like qt, gtk, 
etc. I have been playing around with Dear ImGui 
(https://github.com/ocornut/imgui) which has become quite popular. A 
test using ImGui and looks for PVs from the example ioc app can be found 
here https://github.com/whit2333/imgui_DM .

My initial take away: It was easier to develop my own DM than build most 
of the existing display mangers. I am not sure if this speaks to the 
awesomeness of Dear ImGui, or the sad state of existing DMs (but not you 
MEDM, you are my rock).

In summary, I would like to develop a new display manager around Dear 
ImGui and any feedback or comments on the idea would be great.

Cheers,
Whit

PS This repo was super useful 
(https://github.com/mdavidsaver/cmake4epics) and cmake could make life 
easier by replacing many parts of the -- let's say, unique -- "Epics 
build system".