Short keys for hiding/protecting objects of a symbol

[dg0yt]

oskarlin reported on Sourceforge [tickets:#279]:

When drawing my maps I often want to turn on and off some layers/ symbols and right now one has to right click on the symbol and select "Hide objects..". This is slow. Could you assign a key for toggling symbols on and off? Thanks!

[florianlang]

I second this - I regularly want to turn some layers off and on to do some filling. A hotkey would be much appreciated.