Hide/Show items disabled

Hello guys,

I have a strange problem.

The hide/show items drop down menu doesnt let me choose anything to turn on or off except two icons. Some days ago i could hide and show them.

The strange thing is that the subassemblies included in the main assembly have no problem to hide/show those items when they are opened.

Is it a button or something else which activates or deactivates it?

Thanks

SolidworksUser Interface