In Nautilus, I sometimes want to change the `mode` of the `side-pane` (Tree, Places, etc). 

This can be done via the a mouse click on the drop button at the top of the side-pane.  

...but there is no hot-key/accelerator-key to quickly display this drop-list. 

I usually prefer the keyboard for basic navigation, and this lack of simple keyboard navigation is a pain in the proverbial. 

If there were even a menu item to jump across to the side-pane, it wouldn't be such a pain (bad pun)... and I could just set the menu-item's accelerator key... but there isn't such a menu item!

Can I create a menu-item for this particlar chore?  

or, is there already a hot-key for this?  

(Jumping directly across to the side-pane would be enough. Dropping the list is ideal)

Ctrl+Tab does some sort of navigation, but it seems to stop at every control on its route, and this results in a varying number of whistle-stops, depending on the state of the rest of the window (eg. Extra pane, Expanded trees...)