Bug 5571 JAR Packager: Reveal first checked project
If the list of projects in the JAR Packager is long it is possible that the shown projects are not checked even though there are checked projects (due to current selection). ==> reveal the first checked project.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/jarpackager/CheckboxTreeAndListGroup.java
*/
	protected void setWhiteChecked(Object treeElement, boolean isWhiteChecked) {
		if (isWhiteChecked) {
			if (!fWhiteCheckedTreeItems.contains(treeElement))
				fWhiteCheckedTreeItems.add(treeElement);
		} else
			fWhiteCheckedTreeItems.remove(treeElement);
	}
	/**
	 *	Handle the collapsing of an element in a tree viewer
	 */
	public void treeCollapsed(TreeExpansionEvent event) {
		
	}
	/**
	 *	Handles the expansionsion of an element in a tree viewer
	 */
	public void treeExpanded(TreeExpansionEvent event) {
		Object item= event.getElement();
		
		
		if (!fExpandedTreeNodes.contains(item)) {
			fExpandedTreeNodes.add(item);
			checkNewTreeElements(getTreeChildren(item));
		}
	}
	/**
	 *  Callback that's invoked when the checked status of an item in the tree
	 *  is changed by the user.
	 */