double-clicking on a file opens it twice

[Damien]

But only for some extensions. files opened with file-roller and shotwell are opened twice when accidentally double-clicked. pdf and txt open once.

I suspect this happen depending on the application design. Some obscure application not specifically designed for elementary may open twice accidentally, wich can lead to problems if the application or the file is heavy.

In order to prevent this, there should be a delay before a second click is taken in consideration.

[Cameron Norman (cameronnemo)]

There is no difference for different file extensions. The only difference is the behaviour of the app when you try to open a file that is already open. Shotwell will open another file, while gedit will just say "you have it right here" and give the window/tab with that file focus.

[Danielle Foré (danrabbit)]

The problem is that you're double clicking. Just click once and that won't happen ;)