Outlook插件在Outlook Online中工作，但不会显示在Outlook客户端中

最近我开发了一个Outlook加载项，它有两个下拉按钮和一个任务窗格按钮 . 加载项在Outlook在线工作正常 . 但是加载项未显示在Outlook客户端功能区中 .

如果我从加载项中删除其中一个下拉按钮，它在所有环境中都能正常工作 .

我读到目前只允许一个级别的下拉列表，但没有任何与下拉列表相关的内容 . 清单中使用的下拉控件数量是否有任何限制？

我在Office 365 Pro Plus上运行，Outlook客户端版本是1804（Build 9226.2114）

我正在使用VersionOverridesV1_0及以下控件：

<OfficeTab id="TabDefault">

          <Group id="msgReadGroup">
            <Label resid="groupLabel" />

            <Control xsi:type="Menu" id="msgReadMenuButton">
              <Label resid="msgReadMenuLabel" />
              <Supertip>
                <Title resid="msgReadMenuLabelTitle" />
                <Description resid="msgReadMenuSuperTipDescription" />
              </Supertip>
              <Icon>
                <bt:Image size="16" resid="mail16" />
                <bt:Image size="32" resid="mail32" />
                <bt:Image size="80" resid="mail80" />
              </Icon>
              <Items>
                <Item id="Item1">
                  <Label resid="Item1Label"/>
                  <Supertip>
                    <Title resid="Item1LabelTitle" />
                    <Description resid="Item1SuperTipDescription" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>

                <Item id="Item2">
                  <Label resid="Item2Label"/>
                  <Supertip>
                    <Title resid="Item2LabelTitle" />
                    <Description resid="Item2SuperTipDescription" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>
              </Items>
            </Control>

            <Control xsi:type="Menu" id="meetingReadMenu">
              <Label resid="meetingReadLabel" />
              <Supertip>
                <Title resid="meetingReadMenuTitle" />
                <Description resid="meetingReadMenuSuperTipDescr" />
              </Supertip>
              <Icon>
                <bt:Image size="16" resid="icon16" />
                <bt:Image size="32" resid="icon32" />
                <bt:Image size="80" resid="icon80" />
              </Icon>
              <Items>
                <Item id="meetingItem1">
                  <Label resid="meetingItem1Label"/>
                  <Supertip>
                    <Title resid="meetingItem1Title" />
                    <Description resid="meetingItem1SUSuperTipDescr" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>
                <Item id="meetingItem2">
                  <Label resid="meetingItem2Label"/>
                  <Supertip>
                    <Title resid="meetingItem2Title" />
                    <Description resid="meetingItem2SuperTipDescr" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>
                </Items>
              </Control>


            <Control xsi:type="Button" id="taskpaneButton">
                <Label resid="taskpaneButtonLabel" />
                <Supertip>
                  <Title resid="taskpaneButtonTitle" />
                  <Description resid="taskpaneButtonSuperTipDescr" />
                </Supertip>
                <Icon>
                  <bt:Image size="16" resid="icon16" />
                  <bt:Image size="32" resid="icon32" />
                  <bt:Image size="80" resid="icon80" />
                </Icon>
                <Action xsi:type="ShowTaskpane">
                  <SourceLocation resid="readTaskPaneUrl" />
                </Action>
              </Control>

            <Control xsi:type="Menu" id="ReadMenuButton">
              <Label resid="ReadMenu" />
              <Supertip>
                <Title resid="ReadMenuSuperTipTitle" />
                <Description resid="ReadMenuSuperTipDescription" />
              </Supertip>
              <Icon>
                <bt:Image size="16" resid="help16" />
                <bt:Image size="32" resid="help32" />
                <bt:Image size="80" resid="help80" />
              </Icon>
              <Items>
                <Item id="ReadItem1">
                  <Label resid="ReadItem1Label"/>
                  <Supertip>
                    <Title resid="ReadItem1Title" />
                    <Description resid="ReadItem1SuperTipDescr" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>

                <Item id="ReadItem2">
                  <Label resid="ReadItem2Label"/>
                  <Supertip>
                    <Title resid="ReadItem2Title" />
                    <Description resid="ReadItem2SuperTipDescr" />
                  </Supertip>
                  <Icon>
                    <bt:Image size="16" resid="icon16" />
                    <bt:Image size="32" resid="icon32" />
                    <bt:Image size="80" resid="icon80" />
                  </Icon>
                  <Action xsi:type="ExecuteFunction">
                    <FunctionName>Function1</FunctionName>
                  </Action>
                </Item>
              </Items>
            </Control>                 
            <!-- Go to http://aka.ms/ButtonCommands to learn how to add more Controls: ExecuteFunction and Menu -->
          </Group>
        </OfficeTab>
      </ExtensionPoint>