Bug 182714 [Contributions] Improve toolbar configurability
bundles/org.eclipse.jface/src/org/eclipse/jface/action/MenuManager.java
if (overrides == null) {
            if (parent == null) {
                overrides = new IContributionManagerOverrides() {
                    public Integer getAccelerator(IContributionItem item) {
                        return null;
                    }
                    public String getAcceleratorText(IContributionItem item) {
                        return null;
                    }
                    public Boolean getEnabled(IContributionItem item) {
                        return null;
                    }
                    public String getText(IContributionItem item) {
                        return null;
                    }
                };
            } else {
                overrides = parent.getOverrides();
            }
            super.setOverrides(overrides);
        }
        return overrides;
    }
    /**
     * Returns the parent contribution manager of this manger.
     * 
     * @return the parent contribution manager
     * @since 2.0
     */
    public IContributionManager getParent() {