title: Prevent QMainWindow from jumping to foreground after closing QDialog
body: <p>I'm developing a Qt-based app, using <code>QMainWindow</code> class for the GUI. This app has a built-in server that listens for requests from my Chrome Browser extension, so that I may import information from current web-page into my Qt-app.</p>
  
  <p>So when I press extension's button in the browser, it sends a signal to my Qt-app, which then pops up a <code>QDialog</code> so that I can add some additional information like tags, etc. When I close the <code>QDialog</code>, I expect to return to the browser, but instead my app's main window pops up into foreground if it wasn't minimized (if it was minimized, then it doesn't pop up). </p>
  
  <p>How can I change this behavior, so that I return to my browser after closing <code>QDialog</code>, no matter if the app's main window was minimized or not? If that helps, when creating <code>QDialog</code>, I pass 0 as parent to it.</p>