private void ChangePalette()
{
	this.colorSelector.MainPaletteItemsSource = MyGetSourceMethod();
	this.colorSelector.MainPaletteColumnsCount = 10;	
	UpdatePaletteItems();
}

private void UpdatePaletteItems()
{
	var mainPalette = colorSelector.ChildrenOfType<RadColorPaletteView>().First(x => x.Name == "MainPalette");
	var paletteItems = mainPalette.ChildrenOfType<RadColorPaletteViewItem>();
	var paletteItemsCount = paletteItems.Count();
	var columnsCount = mainPalette.PaletteColumnsCount;
	var orientation = mainPalette.PaletteOrientation;

	for (int i = 0; i < paletteItemsCount; i++)
	{
		var paletteItem = paletteItems.ElementAt(i);

		if ((columnsCount == paletteItemsCount) || (paletteItemsCount / columnsCount == 0))
		{
			paletteItem.PositionState = PositionState.Single;
			return;
		}

		if (orientation == Orientation.Horizontal)
		{
			if (i < columnsCount)
			{
				paletteItem.PositionState = PositionState.Top;
			}
			else if (i > (paletteItemsCount - columnsCount - 1))
			{
				paletteItem.PositionState = PositionState.Bottom;
			}
			else
			{
				paletteItem.PositionState = PositionState.Middle;
			}
		}
		else
		{
			if (i % (paletteItemsCount / columnsCount) == 0)
			{
				paletteItem.PositionState = PositionState.Top;
			}
			else if (((i + 1) % (paletteItemsCount / columnsCount)) == 0)
			{
				paletteItem.PositionState = PositionState.Bottom;
			}
			else
			{
				paletteItem.PositionState = PositionState.Middle;
			}
		}
	}
}