At work I use several applications that use Java Web Start and I launch them multiple times a day.
I noticed recently that my Downloads folder was full of copies of the jnlp files (and also lots of Office documents that were attachments in my web mail client).
Having all this temporary junk in my Downloads folder is really annoying and it didn't used to happen with Opera 12.
How do I make Opera save the file to a temp directory and launch it automatically?