[animated] Menu interaction

This is the last piece to go into the Interaction section of the portfolio. The GIF is quite large, over 4 megs, so do show some patience.

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This is a variation of a stacked menu, whereby opened submenus are collected at the top and the active submenu of choices sits at the bottom. What makes this particular menu different is an ability to navigate to its every corner without needing to change current selection.

Second notable thing is the "currently selected" link at the top line that appears only when the user clicks away from the submenu containing the current selection. It may not look like much, but this ability to always "reset" the menu to its selection-centric state is what make this menu actually usable. It allows synch'ing up the menu with the page content when it's not immediately clear where the current page belongs in the menu.

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In any case, here's the production version. Any thoughts or comments are welcome.