title: oh-my-zsh not applying themes
body: <p>I just set up <code>zsh</code> together with <code>oh-my-zsh</code>. But there's a bit of strange behavior that I cannot understand. If I restart Terminal (or iTerm 2––the behavior is the same in either) the theme specified in <code>~/.zshrc</code> is not loaded. I need to do <code>source ~/.zshrc</code> for it to happen. If I <code>echo $ZSH_THEME</code> I get the theme I specified in <code>~/.zshrc</code>. (And if I add <code>echo "I'm loading it."</code> to the bottom of <code>~/.zshrc</code>, for example, I get the expected message upon opening a new window, etc.)</p>
  
  <p><a href="https://stackoverflow.com/questions/15682456/oh-my-zsh-config-file-not-loading">This question</a> is very similar to mine. But none of the suggestions there appear relevant: the problem there was that some bits of <code>~/.zshrc</code> were not being loaded, whereas in my case it seems they are being 'read' but not 'loaded' if that's a thing.</p>
  
  <p>In case this is relevant: I do not have any files named <code>.zprofile</code> or <code>.profile</code> in my home directory.</p>
  
  <p>Another bit of relevant information. If I change the value of <code>ZSH_THEME</code> in my <code>.zshrc</code> file, I need to source it twice in order to activate the new theme.</p>