I don't think this has been discussed before but apologies if it has...
Similar to the 'skip' feature of a step in TestStand (or comments in text based programming languages) it would be nice to be able to disable parts of the block diagram to bypass parts of the code. I do this often in electronic simulation packages to bypass (route around) parts of a circuit which can be helpful in design or debugging by isolating areas or switching off functionality. In this way you don't have to delete anything to bypass it. To show which parts are disabled in the block diagram those parts would be greyed out or ghost. This of course may also affect controls and indicators which should similiarly be ghost (which has already been suggested to signify hidden controls/indicators).
I guess the alternative is to use case statements with false constants but this can mean creating space and making a mess.
