How to make default planes visible

Hello

I am brand new to Solidworks and just started learning it.

My first question: why do my default coordinate planes (Front, Top and Right Plane) not stay visible when I am doing an assembly? They are always there in a part editing session and that's great, but how can I make them permanently visible in an assembly as well? After "Show"-ing them in the assembly tree, they disappear as soon as I click on the canvass. I'm sure it's a setting somewhere...

I have the student edition 2012-2013.

Thanks all.

SolidworksAssemblies