Undo accidentally minimized desktop (now all desktop icons gone)

If you have a window active and hit "[Alt]+[Space],[N]", that window will be minimized.

It has happened to me a number of times that I did this while the topmost window was in fact inactive (meaning the desktop had focus) -- in those instances, it was the desktop that got minimized, thus hiding all my desktop icons (on all my workspaces).

This must be a bug, or at least a misfeature, of Linux Mint MATE v17.0, 64-bit edition (and possibly others).

How do I unminimize the desktop, other than logging out and in again?