Curtain Call
A full screen menu that is your own canvas frame. The button opens it over the page as a dialog: focus moves in and stays in, Escape closes it and hands focus back, the page behind can’t be scrolled or pressed, and the link to the page being shown is marked by itself. The iris reveal opens it out of the button.
MajeDesigns
Press Menu.
This block stands in for a page. The menu opens over the whole window, out of the button, and while it is open nothing here can be scrolled, pressed or reached with Tab.
Press Menu. The menu is a frame drawn on the canvas, stretched to the window, and its link to this page is underlined by itself. Tab walks the menu and never leaves it, Escape closes it and focus goes back to the button, and the page behind stays where it was.
The same component As drawn: the frame keeps its own 420 px at the right and slides in over a backdrop. A press on the backdrop, the close button or Escape closes it.