I am very sharing this informations too.
Probably best way is to create a new post for each case.
1°/
Add ID number for frames. is very great idea !
With 2 or 3 cubic rooms program could be an answer.
But with a complete house, and complex or small interiors the only colors are difficult to work with.
This is an very great idea, very helpfull and improve productivity, less time and more easy to work.
Please add it asap.

2°/
Stair
How can we work with different levels when there are stairs. I meet same problem too.
3°/ - Can't work witt invisible lines.
Not sure to understand about your problem.
But I met a problem with lines a created in the scene A, and the scene B don't display me all of my vertical lines.
4°/ Nothing I marked in the photo is not working.
During two or three projects i met this same problem, impossible to click on it.
After closed my webbrowser and the testingserver.exe and re-launch testingserver.exe i had access to the different scenes.
Could be a way for you too ?
5°/ Can't import a new scene.
This is a know problem we have the information (officialy).
With small project it's doesn't matter. With big project it's a big disaster.
But if this problem could be solved it will be great.
Jordy, E3 is great idea.
But I share the impression/feeling of alicanyildiz.
Have to consolid for Windows, first step. And try your beta on Windows first.
With 1.20Kr + Navigator plugin + E3 this is not a low cost software.
Program can't stay a one-man software.
We need a true after-sales support.
For this moments I spend a lot of time trying to make it work :
. I can't recommand it
. Projects I promised to my customers (from dec.2019) are still waiting and all of them will be closed soon because of problems and spend time to work on it.
Today I am seriously taking a look about MatterP.