Bug 131771 Match animated message behaviour in Preferences
An enhancement should be made to Preferences so that warnings and errors show up in a sliding message area like it they do in TitleAreaDialog.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceMessageArea.java
case IMessageProvider.WARNING:
            newImage = JFaceResources.getImage(Dialog.DLG_IMG_MESSAGE_WARNING);
            break;
        case IMessageProvider.ERROR:
            newImage = JFaceResources.getImage(Dialog.DLG_IMG_MESSAGE_ERROR);
            break;
        }
        messageArea.setVisible(true);
        messageArea.moveAbove(null);
        messageArea.setImage(newImage);
        
        messageArea.setText(shortenText(newMessage,messageArea, 
        		newImage.getBounds().width + IDialogConstants.HORIZONTAL_SPACING));
        messageArea.setToolTipText(newMessage);
        lastMessageText = newMessage;
        
		int bottom = messageArea.getParent().getBounds().height;
        Rectangle titleLabelBounds = titleLabel.getBounds();
        if(Policy.getAnimator().getAnimationState() == ControlAnimator.CLOSED || 
           Policy.getAnimator().getAnimationState() == ControlAnimator.CLOSING){
            if(Policy.getAnimator().getAnimationState() == ControlAnimator.CLOSED) {
    			messageArea.setBounds(
    					titleLabelBounds.x,
    					bottom,
    					titleLabelBounds.width,
    					messageArea.computeSize(SWT.DEFAULT,SWT.DEFAULT).y);
    		}
    		Policy.getAnimator().setAnimationState(ControlAnimator.OPENING);
    		Policy.getAnimator().setVisible(true, messageArea);
        }