title: Order of Bootstrapper actions
body: <p>I have a bootstrapper with custom UI, 1 msi package and some prerequisites. What I want to do is to do the detection of prerequisites in custom UI and then overwrite one of the variables in bundle element to either install the prerequisite or not.</p>
  
  <p>So basically:</p>
  
  <pre><code>    &lt;Variable Name="VCRedist2010SP1_x86" Value="TRUE"/&gt;
  &lt;Chain&gt;    
    &lt;ExePackage Id="VCRedist2010SP1_x86" Cache="no" Compressed="yes" PerMachine="yes" Permanent="yes" Vital="yes" InstallCommand="/q"
      SourceFile="E:\Redist\vcredist_2010_SP1_x86.exe"
      DetectCondition="NOT VCRedist2010SP1_x86"/&gt;
  ...      
  &lt;/Chain&gt;
  </code></pre>
  
  <p>And then from my UI I overwrite the <code>VCRedist2010SP1_x86</code> variable.
  The problem is that the check of the <code>DetectCondition</code> occurs before I overwrite the variable. Here's the log:</p>
  
  <pre><code>Condition 'NOT VCRedist2010SP1_x86' evaluates to false.
  Setting string variable 'VCRedist2010SP1_x86' to value 'FALSE'
  </code></pre>
  
  <p>The question is if it can work like this at all or do I always have to do the detection inside XML with RegistrySearch, for instance?</p>