Blank resolution causing problems

[Gervase Markham]

Nick Barnes wrote:
> I don't understand.  Why is the special string "" more difficult to
> handle than the special string "[None]" (or "Sproink!" or "42")?

Two reasons:

1) The way TT, GD and URLs treat blank values There's various different 
aspects to this problem, but none of them do exactly the right thing.

2) The fact that "" is not a useful label for a line on a graph 
representing "no resolution", whereas "[None]" (or even "---", if it's 
used elsewhere in the UI) is.

Gerv