This was an interesting one. If you "dock" a window in Rider while having 2 solutions opened (in 2 different Rider "instances"), and then refocus other solution, NCrunch keeps flickering back and forth forever until you kill the nCrunch.Rider.EngineHost processes.
What I did to repro :
1. Create 2 projects in dir/proj1 and dir/proj2
2. Create 2 solutions, proj1.sln containing proj1 and proj2, proj2.sln containing only proj2.
3. Ensure NCrunch tests are visible but not NCrunch processing queue. Open up both solutions in different Rider windows.
4. In proj1.sln, show NCrunch processing queue and dock it somewhere. Note: Just making it visible/non visible does not seem to repro behaviour. I had to dock it to different locations.
5. Go back to proj2.sln, NCrunch now seems to refresh windows forever, getting confused if it should show proj1.sln view or proj2.sln view.
dotnet new classlib -o proj1
dotnet new classlib -o proj2
dotnet add .\proj1\ package NUnit
dotnet add .\proj2\ package NUnit
dotnet new sln -n proj1
dotnet new sln -n proj2
dotnet sln .\proj1.sln add .\proj1\
dotnet sln .\proj1.sln add .\proj2\
dotnet sln .\proj2.sln add .\proj2\
p.s. When I try to load these 2 solutions simultaneously I also managed to get a corrupted NCrunch menu, sent a separate bug report for that d.s.
Screencast:
[img=https://i.imgur.com/bgOPgCl.gif]NCrunch win loop[/img]