I develop Dart with WebStorm. I have a server-project, a client-project and some shared code.
Is it possible to create a project solution, containing several Dart projects (like you can do in VisualStudio)? Or is it common to develop each project in it's own WebStorm window?
You can put the project directories together in a directory and then open that directory instead.
There are also ways with project root configurations to do that with projects that are not in the same directory but I did't bother to try to understand how this exactly work.
I moved away from this setup and use different windows for different projects a while ago because I don't want to maintain project configurations. I have many Dart projects that are reusable packages that I use in many other projects.
Using one window for one Dart package seems to be the easiest setup. I configured keyboard shortcuts (there are probably defaults anyway) for easier switching between WebStorm windows.