The plot properties of the legend cannot be modified if the plot number is too large in a waveform chart

[hans17]

Oops, I should have said RavensFan, not Ben.  Got confused with a different thread.  Sorry RavensFan! 

[vax]

The bug is described in the following KB:

Plot Visibility Not Working in LabVIEW Chart Legend - National Instruments (ni.com)

I attach a workaround using a dummy graph and a scrollbar control.