The "All repositories" tab should open as a top-level view/route
Currently when you try to access the list of all repositories, it opens beneath the current workspace tab. Then when you choose "View branch explorer" on a project, it opens another sub-workspace tab so now my workspace has two branch explorer tabs open in it, and one of them is not even related to the workspace. Clearly this is not the right place for these tabs to open. The Mac client does better by opening the repository list and workspaces in new windows. I'm sure you can come up with a better placement in the Windows client- for example, open "All repositories" as a top level tab anchored on left or right of the tab bar, and create a mock workspace to view the branch explorer of a repository not checked out locally.