How to reference an assembly or project in PL Editor

I have a .csproj that contains all my additional classes and methods that I use again and again with Indicators, Signals and Functions.
I try to add that to the PLStudies2010.sln and reference in PLStudies2010.csproj, that works until I reopen the solution from PLEditor, it looks like the Editor is resetting the .sln file and removing the reference to my project.
I looked at:
https://www.multicharts.com/trading-sof ... 12/Express
And it says "NOTE: Any reference to the other assemblies should be added ONLY via PLEditor .NET." , but there is no place in PLEditor where you can add a reference!
How can I add a reference to My.csproj in the PLStudies2010.sln and reference it in PLStudies2010.csproj?

You need to compile 'My' and then add a reference to the DLL.

You add the reference by right clicking in PLEditor > References... > Add Reference

If you want to make changes to your project, you will need to close MultiCharts. You can't recompile your project while MultiCharts has it in memory, and there is no way to release it.

It is really not a good solution, but that is how it's done.