OK yes I understand better now. I never realized that other browsers apparently don't offer the "open with default application" option in the download dialog, like Opera does.
And actually quite some other applications do this (open as a temporary file) as well, it's a very common pattern: 7-Zip, FileZilla, to name a few.
And even if you didn't, there's always a temp directory that gets cleaned next reboot. Though I agree, the browser should take care of this, like most apps.
Default application, yes. A browser tab, no. When I just want to look at an image, firefox is largely preferable to gimp. When I have a bunch of pdfs, firefox tabs are easier to manage than evince windows.
And actually quite some other applications do this (open as a temporary file) as well, it's a very common pattern: 7-Zip, FileZilla, to name a few.
And even if you didn't, there's always a temp directory that gets cleaned next reboot. Though I agree, the browser should take care of this, like most apps.