<Menus>
  <Menu guid="guidCmdSet" id="packageMenu" priority="0x0300" type="Menu">
    <Parent guid="guidSHLMainMenu" id="IDG_VS_CTXT_PROJECT_BUILD" />
    <CommandFlag>DynamicVisibility</CommandFlag>
    <CommandFlag>DefaultInvisible</CommandFlag>
    <Strings>
      <ButtonText>CPSProject</ButtonText>
      <CommandName>CPSProject</CommandName>
    </Strings>
  </Menu>

<Groups>
  <Group guid="guidCmdSet" id="packageMenuGroup" priority="0x0600">
    <Parent guid="guidCmdSet" id="packageMenu" />
  </Group>
</Groups>

<Button guid="guidCmdSet" id="specialBuildActionId" priority="0x0100" type="Button">
    <Parent guid="guidCmdSet" id="packageMenuGroup" />
    <CommandFlag>DynamicVisibility</CommandFlag>
    <Strings>
      <ButtonText>Special build</ButtonText>
    </Strings>

protected override async System.Threading.Tasks.Task InitializeAsync(System.Threading.CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
{
    // Initialize the Fluent Migrator Menu, should only be visible for projects with FluentMigrator reference
    var mcs = await GetServiceAsync(typeof(IMenuCommandService)) as OleMenuCommandService;
    var menuCommandId = new CommandID(packageCmdSetGuidString, 0x1010);
    var menuItem = new OleMenuCommand(null, menuCommandId);
    menuItem.BeforeQueryStatus += MenuItem_BeforeQueryStatus;

    mcs.AddCommand(menuItem);
}

private void MenuItem_BeforeQueryStatus(object sender, EventArgs e) =>
    ((OleMenuCommand)sender).Visible = ???;