Bug 46351 Call Hierarchy must not implement IViewSite [call hierarchy]
I20031105 The call hierarchy component implements IViewSite which is not allowed. There seems to be no reason for doing so: the CallHierarchyViewPart should directly set the selection provider to its site.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/OpenCallHierarchyAction.java
public void selectionChanged(IStructuredSelection selection) {
        setEnabled(isEnabled(selection));
    }
    
    private boolean isEnabled(IStructuredSelection selection) {
        if (selection.size() != 1)
            return false;
        Object input= selection.getFirstElement();
        if (!(input instanceof IJavaElement))
            return false;
        switch (((IJavaElement)input).getElementType()) {
            case IJavaElement.METHOD:
                return true;
            default:
                return false;
        }
    }
    
    /* (non-Javadoc)
     * Method declared on SelectionDispatchAction.
     */
	public void run(ITextSelection selection) {
        IJavaElement input= SelectionConverter.getInput(fEditor);
        if (!ActionUtil.isProcessable(getShell(), input))
            return;     
        
        IJavaElement[] elements= SelectionConverter.codeResolveOrInputHandled(fEditor, getShell(), getDialogTitle());
        if (elements == null)
            return;
        List candidates= new ArrayList(elements.length);