In previous versions of Toad, it was possible just to close the Editor's Navigator pane and then when Toad was closed and re-launched the Navigator pane would not display. In Toad 11, however, closing the Navigator does not permanently hide it.
How do you get rid of the pane permanently?
1. Close the Navigator window for the 'SQL' tabs
2. Click the 'Save Desktop' button on the Editor toolbar
3. Either create a new layout name or overwrite the 'SQL' layout. If you create a new layout name, then make sure this is selected when you run up an editor.
4. Repeat for a PL/SQL tab if required
5. Close and re-launch Toad and you will find that the Navigator pane is no longer displayed.
6. If you need to restore the default layout at any time, use the dropdown next to 'Save Desktop' button and select 'Restore Default Desktop'