XmChangeColor handles all color modifications for the
specified widget when a new background pixel value is specified.
The function recalculates the foreground, select, and shadow
colors based on the new background color and sets the corresponding
resources for the widget. If a color calculation procedure has
been set by a call to XmSetColorCalculation, XmChangeColor
uses that procedure to calculate the new colors. Otherwise, the
routine uses a default procedure.
widget
Specifies the widget ID whose colors will be updated