title: What is a changelist in IntelliJ IDEA? A list of changes compared to what? An accurate explanation is sought for
body: <p>What is a changelist in IntelliJ IDEA? 
  A list of changes compared to what?
  What does it mean that I can have multiple changelists? </p>
  
  <p>Especially, when I revert back to an earlier version (using VCS) IntelliJ wants to create a new changelist for that. Why? In that case the changes will be related to what? Let's say I revert to version 9 from version 23. Then the changeslist will contain the changes between version 23 and 9 or between 8 and 9? </p>
  
  <p>I tried to read the documentation but it did not give me any enlightment at all.</p>
  
  <p>Is the IntelliJ changelist the same as, for example, the concept of changeset in Mercurial, in which case the changelist is just an other name for a node in the revision history graph, conceptually?</p>