from being None. If the value of the control is currently None,
ie. the control is empty, then the value will be changed to that
of the lower bound of the control, or 0 if no lower bound is set.
from being None. If the value of the control is currently None,
ie. the control is empty, then the value will be changed to that
of the lower bound of the control, or 0 if no lower bound is set.