Bug 312540 [LinkedResources] Copy resource in Navigator and Project Explorer always shows dialog
N20100511-2000. When copying an IFile from one to another folder in the Navigator or Project Explorer, I always get the dialog no matter how I've set the preferences on the 'Linked Resources' page (even if I disable linked resources).
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/navigator/NavigatorDropAdapter.java
/**
     * A flag indicating that overwrites should always occur.
     */
    private boolean alwaysOverwrite = false;
    /**
     * The last valid operation.
     */
    private int lastValidOperation = DND.DROP_NONE;
    /**
     * Constructs a new drop adapter.
     * 
     * @param viewer the navigator's viewer
     */
    public NavigatorDropAdapter(StructuredViewer viewer) {
        super(viewer);
    }
    /*
     * @see org.eclipse.swt.dnd.DropTargetListener#dragEnter(org.eclipse.swt.dnd.DropTargetEvent)
     */
    public void dragEnter(DropTargetEvent event) {
        if (FileTransfer.getInstance().isSupportedType(event.currentDataType)
                && event.detail == DND.DROP_DEFAULT) {