Hiding all nodes produces error messages

[bestchai]

Selecting 'Hide' for every node puts them all in the margin, but also creates a string of error messages to appear in the console:

Error: attribute transform: Expected number, "translate(NaN,0)". ... Error: attribute x1: Expected length, "NaN". ...

Ideally, there would be no error messages.

[Issue created by grahamstl: 2017-03-26]

[Comment created by bestchai: 2017-03-26] I think that the best solution to this is to disallow the user from hiding every node. There is no good use case for this.