Bug 38247 [Viewers] [Javadoc] Incomplete javadoc for DialogCellEditor
The javadoc for #openDialogBox() does not say how to indicate that the dialog box was canceled. The de-facto behaviour is that if null is returned, it is considered as "cancel".
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/DialogCellEditor.java
* The value of this cell editor; initially <code>null</code>.
	 */
	private Object value = null;
	
	static {
		ImageRegistry reg = JFaceResources.getImageRegistry();
		reg.put(CELL_EDITOR_IMG_DOTS_BUTTON, ImageDescriptor.createFromFile(DialogCellEditor.class, "images/dots_button.gif"));
	}
	/**
	 * Internal class for laying out the dialog.
	 */
	private class DialogCellLayout extends Layout {
		public void layout(Composite editor, boolean force) {
			Rectangle bounds = editor.getClientArea();
			Point size = button.computeSize(SWT.DEFAULT, SWT.DEFAULT, force);
			if (contents != null)
				contents.setBounds(0, 0, bounds.width-size.x, bounds.height);
			button.setBounds(bounds.width-size.x, 0, size.x, bounds.height);
		}
		public Point computeSize(Composite editor, int wHint, int hHint, boolean force) {
			if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
				return new Point(wHint, hHint);
			Point contentsSize = contents.computeSize(SWT.DEFAULT, SWT.DEFAULT, force); 
			Point buttonSize =  button.computeSize(SWT.DEFAULT, SWT.DEFAULT, force);
			
			
			
			Point result = new Point(buttonSize.x,
							        Math.max(contentsSize.y, buttonSize.y));
			return result;