title: Git: Changes to new branch reflected on master until first commit
body: <p>Simple git functionality question. I create a new branch, checkout that branch, and make changes to newbranch.  Prior to the first commit on newbranch, I'm seeing that those changes are shown when doing <code>git status</code> from master as well as newbranch.  If I stage those changes while on newbranch, they show up staged on master.  It is not until I commit these changes to newbranch that master appears to be separated.  A) am I crazy?  B) What is the logic behind this?</p>
  
  <p>There is a similar question <a href="https://stackoverflow.com/questions/22796711/git-status-on-master-and-branches">here</a> with no answer.</p>