title: Avoid Vim keeping closed buffers open in the background
body: <p>After doing a complete re-setup of my Vim environment using various standard extensions there is one behavior that annoys me quite much:</p>
  
  <p>When I open a file in a split window and close that window again (":wq") Vim seems to keep the file buffer open in the background. When I now try to open the file in a different shell tab in a new Vim instance, the swap file still exists, what keeps me from editing the file.</p>
  
  <p>I suppose there is a setting which makes Vim keep buffers open but hidden when I close the split, but I could not find out which one it is. What I actually desire is, that Vim really closes the buffers when I close the splits, so that I can open the corresponding files again in a parallel Vim session.</p>
  
  <p>What I expect is, that the buffer is closed as soon as the last window showing it is closed via ":q".</p>