Working with more than one project

I’m looking for project management software and testing some of them. Ganttproject is very close to the final, but I have one noob question.
Can I work with more than one project at a time?
I follow 5-10 (simple) projects simultaneously and want to see their timelines/milestones on one screen.
Is this possible?

An idea - maybe I can create projects as tasks to follow all of them on one screen?

Did you try starting multiple instances of GanttProject? It works fine.

No, I didn’t try. But it looks strange to me and it still doesn’t show all projects in one calendar view. I think this is a very common way of working with projects.
I will try to create tasks for projects and indent tasks for tasks (of projects).