title: WiX toolset execute custom action after installation and wait for completion
body: <p>I want to execute my .exe file, which displays <code>MessageBox</code> and exits upon clicking OK. <code>CustomAction</code> should be executed after installation is finished, but before displaying <code>Finish</code> dialog. Problem is, that I'm not able to set main installer window to wait for clicking on OK button (<code>Finish</code> dialog is displayed directly, therefore main window can be completely closed without clicking OK button).
  WiX Toolset version: v3.10</p>
  
  <p>Product source code:</p>
  
  <pre><code>&lt;Property Id="WixShellExecTarget" Value="[#ExeId]" /&gt;
  &lt;InstallExecuteSequence&gt;
    &lt;Custom Action="LaunchExe" After="InstallFinalize" /&gt;
  &lt;/InstallExecuteSequence&gt;
  &lt;CustomAction Id="LaunchExe" BinaryKey="WixCA" DllEntry="WixShellExec" Execute="immediate" Return="check" Impersonate="yes" /&gt;
  </code></pre>
  
  <p>Component source code:</p>
  
  <pre><code>&lt;Component Id="ExeId" Directory="APPLICATIONFOLDER" Guid="*"&gt;
    &lt;File Id="ExeId" Source=".\ExeName.exe" KeyPath="yes" Checksum="yes" /&gt;
  &lt;/Component&gt;
  </code></pre>