Bug 36518 call hierarchy: 'refresh' should available only in dropdown menu
toolbar button is not conventional and not accessible we should remove it from there and put in the dropdown menu (context menu is ok, i guess)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/CallHierarchyViewPart.java
fDialogSettings = JavaPlugin.getDefault().getDialogSettings();
        fMethodHistory = new ArrayList();
    }
    public void setFocus() {
        fPagebook.setFocus();
    }
    /**
     * Sets the history entries
     */
    public void setHistoryEntries(IMethod[] elems) {
        fMethodHistory.clear();
        for (int i = 0; i < elems.length; i++) {
            fMethodHistory.add(elems[i]);
        }
        updateHistoryEntries();
    }
    /**
     * Gets all history entries.
     */
    public IMethod[] getHistoryEntries() {
        if (fMethodHistory.size() > 0) {
            updateHistoryEntries();
        }
        return (IMethod[]) fMethodHistory.toArray(new IMethod[fMethodHistory.size()]);
    }
    /**
     * Method setMethod.
     * @param method
     */
    public void setMethod(IMethod method) {