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/dialogs/TitleAreaDialog.java
if (warningMessage == null) {
        	if(messageArea != null && !showingError)
           		setMessageAreaVisible(false);
        	
            if (showingWarning)
                showingWarning = false;
         } else {
            if (!showingWarning)
                showingWarning = true;
            warningMessage = newMessage;
            if(messageArea == null){
            	
            	messageArea = new MessageArea(titleArea, SWT.NULL);
            	messageArea.setBackground(messageLabel.getBackground());
       		
            	Policy.getAnimator().setAnimationState(ControlAnimator.CLOSED);
            }
            
            messageArea.setText(warningMessage);
            messageArea.setImage(JFaceResources.getImage(DLG_IMG_MESSAGE_WARNING));
            setMessageAreaVisible(true);
         }
        int verticalSpacing = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_SPACING);
        int horizontalSpacing = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_SPACING);
        setLayoutsForNormalMessage(verticalSpacing, horizontalSpacing);
    }
}