Bug 42068 Pref Pages button order
The button order of: New.../Add... Edit... Remove Should be the same on the following preference pages: Classpath Variables Debug/Detail Formatter Editor/Templates Installed JREs Organize Imports Task Tags @@@ There should be no extra space on: Classpath Variables Task Tags @@@@ The "Up" and "Down" Buttons on Organize Imports should be placed after "New...", "Edit...", and "Remove" for consistency. There should be an extra space between "Remove" and "Enable All" on Debug/Step Filtering for consistency. There should be an extra space between "Remove" and "Search" on Installed JREs for consistency.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/dialogfields/ListDialogField.java
* Gets the elements shown in the list.
	 * The list returned is a copy, so it can be modified by the user.
	 */	
	public List getElements() {
		return new ArrayList(fElements);
	}
	/**
	 * Gets the elements shown at the given index.
	 */		
	public Object getElement(int index) {
		return fElements.get(index);
	}
	
	/**
	* Gets the index of an element in the list or -1 if element is not in list.
	*/
	public int getIndexOfElement(Object elem) {
		return fElements.indexOf(elem);
	}	
	/**
	 * Replace an element.
	 */		
	public void replaceElement(Object oldElement, Object newElement) throws IllegalArgumentException { 
		int idx= fElements.indexOf(oldElement);
		if (idx != -1) {
			fElements.set(idx, newElement);
			if (fTable != null) {
				List selected= getSelectedElements();
				if (selected.remove(oldElement)) {
					selected.add(newElement);