When you close a tab or window, if the previously-used tab/window was from a different project, the Project Browser "hiccups" as it switches to the other project. If you're trying to close one project (or all windows from a project except for one) without affecting the other open views, this can get extremely annoying. There should at least be an option setting to stay in the same project when closing tabs/windows (requiring you to explicitly choose a view from another project to switch to it).
