Bug 54737 Libraries dialog doesn't remember status of items in library tree
Preferences > Java > Build Path > User Libraries: The dialog does not seem to correctly remember the status of the items in the "Defined user libraries" tree. When I leave the dialog I close (un-cascade) all items. When I open the dialog again, most of the items are open (cascaded) again. This is disturbing because I cannot overview the items. It's like opening the Windows explorer with not only the drives shown but all folders being open.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/dialogfields/TreeListDialogField.java
*/
	public void removeElement(Object element) throws IllegalArgumentException {
		if (fElements.remove(element)) {
			if (fTree != null) {
				fTree.remove(element);
			}
			dialogFieldChanged();
		} else {
			throw new IllegalArgumentException();
		}
	}
	/**
	* Removes elements from the list.
	*/
	public void removeElements(List elements) {
		if (elements.size() > 0) {
			fElements.removeAll(elements);
			if (fTree != null) {
				fTree.remove(elements.toArray());
			}
			dialogFieldChanged();
		}
	}
	/**
	* Gets the number of elements
	*/
	public int getSize() {
		return fElements.size();
	}
	public void selectElements(ISelection selection) {