Attaching a file from DTP3

I needed to upload a PDF from DTP3 to a website. The quickest way I could figure to do this was (once the file open dialog was open in the browser) drag the file from DTP3 to the browser. This isn’t terrible, but I’d prefer an option that doesn’t require using the mouse/trackpad. Are there other ways?

No, there is no way to do this via keyboard controls, at least nothing built in.