If you are working with multiple copies of BuildPlus open and creating / deleting projects in the various copies, it is important that each BuildPlus know which projects exist, etc.
BuildPlus automatically refreshes itself when it becomes the active window, loading all changes which may have been made by any other BuildPluses. This includes the File menu BuildRoots and projects, the state of the toolbar buttons, and the settings for the currently open project.
You can also manually force a refresh. On the Tools menu, click Refresh BuildPlus, or press the F5 key.
Changes to the license, however, require restarting BuildPlus.