Toogle Header GUI

When I click on "View" I see "Toogle Header" with no distinguishing mark on it.

After I have clicked on "Toogle Header", if I click again on the "View":
- "Toogle Header" is still the exact same look as before being selected,
- A more "usual" GUI grammar, on Windows, would be to see a change:
- to checkmark active text options,
- or for the example of Firefox "full screen" icon, to put a dark square below the activated icon.

Start by locating the View menu and its "Toogle Header" item in the notebook GUI. Check how the item looks before and after selection, then make the active state visibly distinct using one of the suggested GUI conventions; done means the selected state is apparent when reopening View.

Written by the indexing model from the issue text.