You can. It’s a dock just like the one on the bottom that linters live in and the one on the right that the Git and GitHub tabs (from the
github package) live in. To see how, just drag a dock item from any other dock next to the tree view tab until you see a blue line appear and release.
If would be great if you could open another project as a tab in this pane, and when clicking, all file tabs in the central pane were changued.
Why not use
project-viewer? It allows you to perform this same activity, except instead of trying to cram a bunch of names into a tiny horizontal tab bar, it organizes your projects vertically with colors and collapsible groups. When you click on a project name, the current window will stay open and all of your open files will swap to the ones you had open on the destination project.