Parallel Processes not working (android apps)

[Wintertech Gaming]

FIRST OF ALL
Let me make it clear that I've scowered the web looking for information concerning this problem and no one has properly addressed it. I am not trying to do anything concerning chrome browser tabs or browser processes. I am speaking specifically about running more than one app at a time without having to use split screen feature. ( Which doesn't even work with android apps)

TL;DR:

[Background apps (usually android) pause when in background. There's no option to change that however I managed to do something that allowed android apps to run even when minimized (alt+tab specifically) 

Apps that run in the background have a black tab while apps that pause immediately have a grey tab. Does this have anything to do with anything, and how to get this working consistently?]

I've downloaded a few android games that I would love to have running in the background and I've tried to no end tampering with flags and dev options. At one point I switched to dev mode and it started working but less than a week later many bugs hindered from laptop from functioning, and I ended up having to hard wipe and reset it, so using dev mode is out of the question. 

Now I don't know what I did but I managed to get it to finally work in beta mode after messing with some flags again. One of the first things I noticed is that apps that continue running in the background have a black colored tab while apps that pause immediately when minimized have a grey tab. 

I want to know if that has something to do with anything at all. So that if any case I need to assist someone else or redo the process on my own laptop I know what I'm doing.

Until I get some substancial responses I'm not going to do anything or tinker with any options for fear of making it stop working again. So far it's the most useful feature on Chromebook I know of but yet there's little to no information on how to do it. And the chrome flag that directly supported the feature was entirely removed over 2 years ago.

Details

Chromebook Software, Beta

[Daniel Clark]

In my experience split screen does work with Android apps, or at least with one Android app and a floating chrome window (YouTube PiP) I use this all the time to play chess with the lichess Android app while watching videos. That specific app doesn't natively support split screen, so I do have to invoke it via the "toolbar" Android app rather than directly from the chrome os launcher. I also had to play with some Toolbar and Android developer settings to get it to work nicely. I'm running in the dev channel with dev mode enabled in Android.