LC 7.1 possible bug

[Richmond]

I'm not sure if this is a bug:

https://www.dropbox.com/s/aat4znrcta95bvg/bugPerhaps.gif?dl=0

I made a moronically simple stack to make numbered roundels, and
once I had got beyond a certain amount the contextual menu of the properties
palette went "sour", and I am now quite unable to select the field 
"Field" within
the group "ww" to enter new numbers.

Richmond.