Bugzilla

**Possible starting point in code**

The function `onSMIMEBeforeShowHeaderPane()` looks as if it should do exactly what is needed to prevent this bug.
So probably for some reason, either it's not running at all or it fails to achieve.
No errors in console afsics.

https://searchfox.org/comm-central/rev/aa91ead1bc230db8903fc6b0fef946c2535fbf0b/mail/extensions/smime/content/msgHdrViewSMIMEOverlay.js#360-371

```
function onSMIMEBeforeShowHeaderPane() {
  // For signed messages with differing Sender as signer we force showing Sender.
  // If we're now in a different message, hide the (old) sender row and remove
  // it from the header view, so that Sender normally isn't shown.
  if (
    "sender" in gExpandedHeaderView &&
    !Services.prefs.getBoolPref("mailnews.headers.showSender")
  ) {
    gExpandedHeaderView.sender.enclosingRow.collapsed = true;
    delete gExpandedHeaderView.sender;
  }
}
```

**Possible starting point in code**

The function `onSMIMEBeforeShowHeaderPane()` looks as if it should do exactly what is needed to prevent this bug.
So probably for some reason, either it's not running at all or it fails to achieve.
No errors in console afsics.

https://searchfox.org/comm-central/rev/aa91ead1bc230db8903fc6b0fef946c2535fbf0b/mail/extensions/smime/content/msgHdrViewSMIMEOverlay.js#360-371

```
function onSMIMEBeforeShowHeaderPane() {
  // For signed messages with differing Sender as signer we force showing Sender.
  // If we're now in a different message, hide the (old) sender row and remove
  // it from the header view, so that Sender normally isn't shown.
  if (
    "sender" in gExpandedHeaderView &&
    !Services.prefs.getBoolPref("mailnews.headers.showSender")
  ) {
    gExpandedHeaderView.sender.enclosingRow.collapsed = true;
    delete gExpandedHeaderView.sender;
  }
}
```

https://searchfox.org/comm-central/search?q=onSMIMEBeforeShowHeaderPane&path=

**Possible starting point in code**

(updated from Gerald's Bug 1670243 Comment 24 - thanks for the pointer!)

The function `onSMIMEBeforeShowHeaderPane()` looks as if it should do exactly what is needed to prevent this bug.
So probably for some reason, either it's not running at all or it fails to achieve.
No errors in console afsics.

https://searchfox.org/comm-central/rev/aa91ead1bc230db8903fc6b0fef946c2535fbf0b/mail/extensions/smime/content/msgHdrViewSMIMEOverlay.js#360-371

```
function onSMIMEBeforeShowHeaderPane() {
  // For signed messages with differing Sender as signer we force showing Sender.
  // If we're now in a different message, hide the (old) sender row and remove
  // it from the header view, so that Sender normally isn't shown.
  if (
    "sender" in gExpandedHeaderView &&
    !Services.prefs.getBoolPref("mailnews.headers.showSender")
  ) {
    gExpandedHeaderView.sender.enclosingRow.collapsed = true;
    delete gExpandedHeaderView.sender;
  }
}
```

https://searchfox.org/comm-central/search?q=onSMIMEBeforeShowHeaderPane&path=