When a form start with BindControls = .F.,
all Controlsource are ignored until you set BindControls = .T. for the first time.

But a bug on VFP internal C++ code evaluate every control two time:

form.BindControls = .T.
* this is the evaluation sequence
FormControl1.EvaluateControlSource
FormControl1.EvaluateControlSource  <=== bug
FormControl2.EvaluateControlSource
FormControl2.EvaluateControlSource  <=== bug
....
FormControlN.EvaluateControlSource
FormControlN.EvaluateControlSource  <=== bug

This happens only for the first transition .F. -> .T.,
eventual other changes of BindControls from F. to T. are corrected.

In the normal use of ControlSource it is not a large problem,
in form many complexes can it are to us a useless slowing down.

If a ControlSource with an expression or a Property with Property_Access is used,
the thing can be more annoying.