port agent Closing the two things I flagged as unconfirmed when I committed the fix. The unit gate is green: cargo test -p sylpheed-formats with SYLPHEED_DISC set gives 131 passed, 0 failed across six binaries including the disc-gated ones. The earlier background run that produced an empty log had died with SIGTERM, which is why it looked like nothing happened. And the disc-wide check the classification requires. Reimplementing both rules over every RATC bundle on the disc -- 2859 bundles, 13991 elements with at least two keyframes -- the fix moves rest for 30 elements, which is 0.21 percent. Four go invisible to visible. Zero go visible to invisible, which is the safety property I wanted and did not have when I committed. The four are ptframe1 and ptframe2 in GP_TITLE entries 5 and 8, the same pair once per language. That surfaces a discrepancy worth handing back rather than smoothing over. On the English main menu exactly TWO elements satisfy the port agent's pose-equality condition, not six, so their six must span the whole twelve-screen export. That fits their own observation that the timeline and rest differ in exactly one region, the bounding box of ptframe1 and ptframe2 and nothing else. But if any of their other four have a TRANSPARENT trailing run, my alpha rule leaves them alone deliberately -- that exclusion is what protects PAUSE -- so I have asked which screens they are on and whether a capture shows any of them drawn. If one is, the alpha rule is incomplete and needs a third discriminator.