view properties with no data file loads creates ugly error message

[bnlawrence]

Version 3.3.0
if you haven't loaded any data, then view properties stack dumps in the output messages. We should handle that more gracefully.

[sadielbartholomew]

Thanks for the bug report, @bnlawrence. Keep them coming as you spot them and once I get round to organising cf-view (shortly) I will address them.