protected internal void CalculateWidths()
{
if (totalWidth <= 0)
return;
float total = 0;
int numCols = NumberOfColumns;
for (int k = 0; k < numCols; ++k)
total += relativeWidths[k];
for (int k = 0; k < numCols; ++k)
absoluteWidths[k] = totalWidth*relativeWidths[k]/total;
}