If, in MacOS, I can drag a file onto a taskbar icon to open the file in whatever program I dropped it on... MacOS already does that. You're not going to drag a

If, in MacOS, I can drag a file onto a taskbar icon to open the file in whatever program I dropped it on... MacOS already does that. You're not going to drag a video file to the spreadsheet app icon with much success, but if the app knows how to handle it then it will work. I can't imagine using an OS these days that doesn't have that functionality.