I found that in the documentation (actual and the one from 2015r1, so no related to API2)
http://documentation.xojo.com/api/deprecated/rectcontrol.html#rectcontrol-visible
The shared example is:
ListBox1.Value = [Me](http://documentation.xojo.com/api/language/me.html).Visible
Me.Visible
, I can understand what it can do, but ListBox1.Value… I do not found an explaining entry in the documentation.