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 Control getTreeControl(Composite parent) {
		if (fTreeControl == null) {
			assertCompositeNotNull(parent);
			fTree= createTreeViewer(parent);
			fTreeControl= (Tree) fTree.getControl();
			fTreeControl.addKeyListener(new KeyAdapter() {
				public void keyPressed(KeyEvent e) {
					handleKeyPressed(e);
				}
			});
			fTree.setAutoExpandLevel(99);
			fTree.setContentProvider(fTreeViewerAdapter);
			fTree.setLabelProvider(fLabelProvider);
			fTree.addSelectionChangedListener(fTreeViewerAdapter);
			fTree.addDoubleClickListener(fTreeViewerAdapter);
			fTree.setInput(fParentElement);
			fTree.expandToLevel(fTreeExpandLevel);
			if (fViewerSorter != null) {
				fTree.setSorter(fViewerSorter);
			}
			fTreeControl.setEnabled(isEnabled());
			if (fSelectionWhenEnabled != null) {
				postSetSelection(fSelectionWhenEnabled);
			}
		}
		return fTreeControl;
	}
	/**
	* Returns the internally used table viewer.
	*/