title: Configure vsdiffmerge for multiple files at once
body: <p>I am using git 1.9.4 for windows from (<a href="http://git-scm.com/download/win">http://git-scm.com/download/win</a>).</p>
  
  <p><code>$ git difftool branchA branchB</code>
  Opens up <code>vsdiffmerge</code> one file at a time for all the files in the diff.</p>
  
  <p><code>$ git difftool --no-prompt branchA branchB</code> attempts to open up all the files at once (what I want to happen) but vsdiffmerge can't handle this properly with any of the bellow happening.</p>
  
  <ul>
  <li>multiple empty instances of vsdiffmerge will open</li>
  <li>an already open instance will have its open tab replaced with the next file in the diff list</li>
  </ul>
  
  <p>How do I configure my difftool so the behavior is one instance of vsdiffmerge, with multiple tabs of all the diffs?</p>
  
  <p>gitconfig:</p>
  
  <pre><code>[diff "astextplain"]
      textconv = astextplain
  [rebase]
      autosquash = true
  
  [diff]
      tool = vsdiffmerge
  [difftool]
      prompt = true
  [difftool "vsdiffmerge"]
      cmd = \"C:\\Program Files (x86)\\Microsoft Visual Studio 11.0\\Common7\\IDE\\vsdiffmerge.exe\" \"$LOCAL\" \"$REMOTE\" //t
      keepbackup = false
      trustexistcode = true
  [merge]
      tool = vsdiffmerge
  [mergetool]
      prompt = true
  [mergetool "vsdiffmerge"]
      cmd = \"C:\\Program Files (x86)\\Microsoft Visual Studio 11.0\\Common7\\IDE\\vsdiffmerge.exe\" \"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\" //m
      keepbackup = false
      trustexistcode = true
  </code></pre>