forcing a docked app to open a file

[popey.marin]

I found recently that if you drag a file on a docked app, you can force this app to try to open it : put a file on the icone of a file that don't want to open it. The icone remain unselected. Now, try to hit the command and option keys at the same time. The icone become selected, and you can force this app to open the file.

[Jasoco]

Cool! I'll find that useful!