#318 Windows - no action on double click if Xena or Viewer open

[Terry O'Neill]

On windows double clicking on a .xena file is set to open that file up in the Xena Viewer. However if Xena or the Xena Viewer is already open then no action occurs when double clicking on a file. In this case this is because Windows is not opening a new occurrence of the Xena Viewer. It would be nice if this situation was catered for.