setRowHeaderCount in WTableView
The method setRowHeaderCount () in WTableView apparently has an undocumented side effect.
During initialization, but after the call to setRowHeaderCount, which is the first call,
as requested in the documentation ("this property must be set before any other settings of the view"),
rows indices are as expected, but during signal handling I have to substract the value of RowHeaderCount
from the column index and the last column of the table is invisible.