[whpalmer4]

Select a project from the sidebar by clicking on it, and that's all that you should see in the main panel. If you then right-click on the name in the sidebar, you'll get a pop-up menu from which you can select Focus whereupon OmniFocus won't even show you the long list of projects in the sidebar until you undo the Focus operation (right-click in sidebar and choose Show All Projects). There are also toolbar buttons you can add via View->Customize Toolbar and menu equivalents.