For the past few weeks I've been trying out unity 2019.2.0b9 and I have found that unity doesn't automatically recognise rider on my Ubuntu 18.04.3 machine. I have to go to preferences --> external tools --> external script editor to manually add it. Once I have set it there, you may think it should work from there whenever you create a new project but no, I have to set it up every single time for a new project and this is annoying. I installed rider using the Ubuntu Software store. If anyone has a solution that would be great or if anyone knows if this has been fixed in the latest revision, then great.