title: Visual Studio Error: Master edit already in progress
body: <p>In source view when I am trying to edit something a dialogue box is coming saying "Master edit already in progress" as shown in the below image</p>
  
  <p><img src="https://i.stack.imgur.com/8dp5Z.png" alt="enter image description here"></p>
  
  <p>What could be the reason ?
  Just closing the form and re-opening it resolves the issue, but I want know, what is happening behind the scene ?</p>