Bug 12329 [Cell Editors] Request:ComboBoxCellEditor READ_ONLY style
Although CCombo accepts SWT.READ_ONLY style, there is no way to specify style when it is used in ComboBoxCellEditor. How about adding createControl(Composite parent, int style) method to ComboBoxCellEditor class?
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColorCellEditor.java
private ImageData createColorImage(Control w, RGB color) {
	GC gc = new GC(w);
	FontMetrics fm = gc.getFontMetrics();
	int size = fm.getAscent();
	gc.dispose();
	int indent = 6;
	int extent = DEFAULT_EXTENT;
	if (w instanceof Table)
		extent = ((Table) w).getItemHeight() - 1;
	else if (w instanceof Tree)
		extent = ((Tree) w).getItemHeight() - 1;
	else if (w instanceof TableTree)
		extent = ((TableTree) w).getItemHeight() - 1;
	if (size > extent)
		size = extent;
	int width = indent + size;
	int height = extent;
	int xoffset = indent;
	int yoffset = (height - size) / 2;
	RGB black = new RGB(0, 0, 0);
	PaletteData dataPalette = new PaletteData(new RGB[] {black, black, color});
	ImageData data = new ImageData(width, height, 4, dataPalette);
	data.transparentPixel = 0;
	int end = size - 1;
	for (int y = 0; y < size; y++) {
		for (int x = 0; x < size; x++) {
			if (x == 0 || y == 0 || x == end || y == end)
				data.setPixel(x + xoffset, y + yoffset, 1);
			else
				data.setPixel(x + xoffset, y + yoffset, 2);