It's #1, but it's the primary selection, not the clipboard. On Linux, there's the clipboard, which is the Ctrl+C/Ctrl+V that most people are familiar with. Th

It's #1, but it's the primary selection, not the clipboard. On Linux, there's the clipboard, which is the Ctrl+C/Ctrl+V that most people are familiar with. There's also the "primary selection", which is the currently highlighted text. That selection can be pasted into a different app or text box with middle click. So you can really quickly do highlight, middle-click, highlight, middle click. The primary selection is stored separately from the clipboard too, so it won't overwrite the contents of such. But, because setting the primary selection is just selecting text, if JS selects text, then it sets the primary selection. Compare with the clipboard: JS cannot normally set the clipboard except in certain contexts (the OP goes into these).