What is it about DataTable Column Names with dots that makes them unsuitable for WPF's DataGrid control?

Question

Run this, and be confused:

Answer 1

The FULL STOP (period/dot) character does not work.
Even escaping with x\002E did not work.

Here is a compromise using the MIDDLE DOT character:

dt1.Columns.Add("a\x00B7name", typeof(string));  
dt1.Columns.Add("b\x00B7name", typeof(string));