Truss Span will not change in model

[jill_m_hanby]

I have modified several trusses and added different length types within the family.  When I flex them, all is well. However when I insert into the model file, the span will not change for each type and the span is grayed out in the properties palette. See attachment.  Can someone explain what I am doing wrong?

[Tom_Kunsman]

Looks like you are editing a Group. I am not sure you can change a parameter in this mode. Try removing the truss from the Group, then change the parameter, then re-add to the group.