The way it works for webapps is that you are only allowed to read or write the clipboard in the event handler for certain events, but it isn’t really watertight

The way it works for webapps is that you are only allowed to read or write the clipboard in the event handler for certain events, but it isn’t really watertight and that sort of mechanism isn’t so feasible outside the web where you don’t have so much control on how programs handle events.