Simplify the option to display (show/hide) the Navigation window
Pressing "n" should simply toggle the display of the Navigation window on/off all at once (both panes).
There is no need to make available an option to turn on only one of the Navigation panes. It's okay to disable this functionality.
The menu option (View > Navigation) should be simpler too. Selecting "Navigation" from the main menu should do the same action as pressing "n". Simplify the "View" menu as follows:
Replace "Window > Nav" with just "Navigation" (not "Nav").
Show a checkmark when appropriate. (Treat the "Navigation" option similar to "Word Tip".)
Add a button to show/hide Navigation pane
create new icon: perhaps 2 panes side-by-side, similar to "1-to-many"?
place button on the toolbar, just below "1-to-many" button, or...
place button on the top bar, next to language drop-down
Additional menu tweaks
Change order of "View" menu options:
Navigation
Toolbar
Word tip
Justify
Prose
Text direction (add shortcut label "L")
Arrowheads
Chunks
Chains
Change "Hide" to "Chains" (which expands to "Track/Resonance/Stack", same as now)
Move the "Tools" option higher in the menu hierarchy:
Change name from "Tools" to "Toolbar"
Move to "View > Toolbar"
Show checkmark when Toolbar is toggled to on/show (same as "Word Tip" etc.)
Change the so-called "grid view" menu option
Move it from the "View" menu to the "Advanced" menu
Simplify the option to display (show/hide) the Navigation window
Additional menu tweaks
Screenshot
Current "View" menu: