Bug 127105 Package explorer hierarchical mode calls ICompilationUnit#getChildren() in PackageExplorerProblemTreeViewer#isExpandable
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
import org.eclipse.jdt.ui.JavaElementSorter;
import org.eclipse.jdt.ui.JavaUI;
import org.eclipse.jdt.ui.PreferenceConstants;
import org.eclipse.jdt.ui.StandardJavaElementContentProvider;
import org.eclipse.jdt.ui.actions.CustomFiltersActionGroup;
import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.dnd.DelegatingDropAdapter;
import org.eclipse.jdt.internal.ui.dnd.JdtViewerDragAdapter;
import org.eclipse.jdt.internal.ui.dnd.ResourceTransferDragAdapter;
import org.eclipse.jdt.internal.ui.filters.OutputFolderFilter;
import org.eclipse.jdt.internal.ui.javaeditor.EditorUtility;
import org.eclipse.jdt.internal.ui.javaeditor.IClassFileEditorInput;
import org.eclipse.jdt.internal.ui.javaeditor.JarEntryEditorInput;
import org.eclipse.jdt.internal.ui.preferences.MembersOrderPreferenceCache;
import org.eclipse.jdt.internal.ui.util.JavaUIHelp;
import org.eclipse.jdt.internal.ui.viewsupport.AppearanceAwareLabelProvider;
import org.eclipse.jdt.internal.ui.viewsupport.DecoratingJavaLabelProvider;
import org.eclipse.jdt.internal.ui.viewsupport.FilterUpdater;
import org.eclipse.jdt.internal.ui.viewsupport.IViewPartInputProvider;
import org.eclipse.jdt.internal.ui.viewsupport.JavaElementImageProvider;
import org.eclipse.jdt.internal.ui.viewsupport.ProblemTreeViewer;
import org.eclipse.jdt.internal.ui.viewsupport.StatusBarUpdater;
import org.eclipse.jdt.internal.ui.workingsets.ConfigureWorkingSetAction;
import org.eclipse.jdt.internal.ui.workingsets.ViewActionGroup;
import org.eclipse.jdt.internal.ui.workingsets.WorkingSetFilterActionGroup;
import org.eclipse.jdt.internal.ui.workingsets.WorkingSetModel;
 
/**
 * The ViewPart for the ProjectExplorer. It listens to part activation events.