This would cause the application to open but not take focus from what you're currently doing.

A bit like the 'Open tab in background' option on some browsers.

Most useful for those applications that take more than an instant to load (MS Office applications, Firefox are good examples of this).

Motivation: I often find that I want my spreadsheet/text/browser application open and ready for something I'm about to do, but don't want to lose focus from the current activity until I'm quite ready, especially if that current activity involves text input.

If this already exists on Linux/Max/Windows I've not yet seen it and would be more than happy to discover this to be baked.