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
* @param viewerSorter The viewerSorter to set
	*/
	public void setViewerSorter(ViewerSorter viewerSorter) {
		fViewerSorter= viewerSorter;
	}
	
	/**
	* Sets the viewerSorter.
	* @param viewerSorter The viewerSorter to set
	*/
	public void setTreeExpansionLevel(int level) {
		fTreeExpandLevel= level;
		if (fTree != null) {
			fTree.expandToLevel(level);
		}
	}	
	
	private void buttonPressed(int index) {
		if (!managedButtonPressed(index) && fTreeAdapter != null) {
			fTreeAdapter.customButtonPressed(this, index);
		}
	}
	/**
	* Checks if the button pressed is handled internally
	* @return Returns true if button has been handled.
	*/
	protected boolean managedButtonPressed(int index) {
		if (index == fRemoveButtonIndex) {
			remove();
		} else if (index == fUpButtonIndex) {