title: vim in tmux background color changes when paging
body: <p>I am using vim in 256 color mode on Solaris (connected via Putty on Windows).  Everything looks great and works fine outside of tmux, but within tmux the background color changes periodically when paging/scrolling through a file.</p>
  
  <p>Here is how it's supposed to look:</p>
  
  <p><img src="https://i.imgur.com/p2VxY.png" /></p>
  
  <p>Here is how it appears after paging around a bit:</p>
  
  <p><img src="https://i.imgur.com/lAI9c.png" /></p>
  
  <p>Thanks!</p>