无法跟踪上下文菜单的Eclipse插件的错误

Question

当我将项目作为Eclipse插件项目运行时，它运行正常。但是当我将它作为Eclipse插件导出并将其复制到Eclipse插件文件夹中时。重新启动eclipse后，上下文菜单没有出现......

为plugin.xml中的上下文菜单定义的配置：

    <extension point="org.eclipse.ui.menus">
        <menuContribution locationURI="popup:org.eclipse.jdt.ui.PackageExplorer">
            <command commandId="patch.easy" label="Add to Patch" style="push">
            </command>
        </menuContribution>
    </extension>
    <extension point="org.eclipse.ui.commands">
        <command defaultHandler="com.createMenu.PatchMenu" id="patch.easy"
            name="Convert"></command>
    </extension>

请帮忙......