* Returns the custom palette in use for this workbook; if a custom palette record
* does not exist, then it is created.
*/
public PaletteRecord getCustomPalette()
{
PaletteRecord palette;
int palettePos = records.getPalettepos();
if (palettePos != -1) {
Record rec = records.get(palettePos);
if (rec instanceof PaletteRecord) {
palette = (PaletteRecord) rec;