Once and for all - how do i make Visual Studio open one instance

I have Visual Studio Community 2015 connected to my Unity 5.4.1f1

I love it but there is one thing that just drives me crazy. Whenever i click on a script in the project it opens a completely new instance of the visual studio…

I looked through some forums and sadly the answers I found are super complicated and I am lazy to go through hundreds of steps.

Does anybody know how to set it up once and for all in a quick easy way so it just keeps one instance per project?



Have you tried Project → Clean Solution, Project → Build Solution?