title: TFS: Merge discard changeset appears as merge candidate when merging in reverse direction
body: <p>I have a question about merging between branches in TFS 2013, specifically about merge discard, that I haven't been able to find an answer for in other threads.</p>
  
  <hr>
  
  <p>Scenario: we have two branches, let's call them <code>$North</code> and <code>$South</code> - to emphasize they are not to be looked upon as source and target (i.e. merging can be done in both directions). <code>$South</code> was branched out from <code>$North</code>.</p>
  
  <p>I check in changeset nr. 1000 to <code>$North</code>, and the changeset appears expectedly as a merge candidate:</p>
  
  <pre><code>&gt; tf merge /candidate $North $South /recursive
  Changeset User  Date  Comment
  1000      Bob   ...   Updating build script
  </code></pre>
  
  <p>Then I do a merge discard because this changeset is not relevant to merge to the other branch, in fact it is not application code but rather configuration specific to the branch:</p>
  
  <pre><code>&gt; tf merge /discard /version:C1000~C1000 $North $South /recursive
  Resolved file1 as KeepYours
  ...
  </code></pre>
  
  <p>I check in the <code>merge discard</code> resulting in changeset nr. 1001. Now changeset 1000 has disappeared from the merge candidate list:</p>
  
  <pre><code>&gt; tf merge /candidate $North $South /recursive
  There are no changes to merge.
  </code></pre>
  
  <p>BUT, now I check the merge candidates in the reverse direction:</p>
  
  <pre><code>&gt; tf merge /candidate $South $North /recursive
  Changeset User  Date  Comment
  1001*     Bob   ...   Merge discard on changeset 1000
  </code></pre>
  
  <p>I even tried to rollback the merge discard again, because I would rather have the change as merge candidate from <code>$North</code> to <code>$South</code> than in the other direction, but the result was just another merge candidate:</p>
  
  <pre><code>&gt; tf merge /candidate $South $North /recursive
  Changeset User  Date  Comment
  1002*     Bob   ...   Rollback on merge discard on changeset 1000
  1001*     Bob   ...   Merge discard on changeset 1000
  </code></pre>
  
  <p>Does anyone know if it is possible at all to completely discard a changeset, and also not having the discard itself appear as merge candidate in the other direction?</p>
  
  <p>(Although I don't know if the contents of my initial changeset is relevant, I can add that my actual changeset 1000 was a change in <code>$North</code> that consisted of a delete on a folder that was also present in <code>$South</code>, and also a folder add.)</p>