<p>Some details:</p><p>This is Linux Zoom 7.1.5. Previously I had 6.6 installed, which didn&#39;t do this.</p><p>It appears to only care about the CLIPBOARD selection – the one with Windows-ish UX, which you typically copy to explicitly with a keystroke such as ^C, and paste from with ^V (or similar). It doesn&#39;t look at PRIMARY, the selection used for trad X11 &quot;just select in this window then middle-click in the other&quot; copy-paste.</p><p>It looks as if it&#39;s detecting changes of clipboard via the XFIXES extension, and whenever the clipboard is claimed by a new owner, it immediately sends that client a paste request.</p><p>I noticed it because I make heavy use of a &quot;one-shot paste&quot; tool which fulfills a single paste request and then terminates. Handy for filling in lots of fields of a web form – queue up pastes of several different things, then go to each form field in turn and just hit paste, bam bam bam. But today, after an apt update, it doesn&#39;t work: my one-shot paste tool terminates as soon as it starts, because (I found out after some debugging) Zoom always requests a paste immediately.</p><p>(Regular readers might recall that around this time _last_ year I caught Slack doing something similar, but only when focus entered the Slack window, and also, they had a configuration option to turn it off. A one-shot paste tool seems to be a good way to notice weird things going on in the X server!)</p>