Maximizing message pane / how to invoke MsgToggleThreadPane()?

[eMPee584]

Browsing through the list of messages, it would be very useful to be able to maximize the message pane.. there once was an addon that did this but it was last updated three years ago and doesn't install on modern versions:

• in tb addons: https://services.addons.thunderbird.net/eN-US/thunderbird/addon/maximize-message-pane/
• Homepage: https://hogi.sakura.ne.jp/en/mmp/mmp_detail.rhtml
• Implementation: https://github.com/cleidigh/ThunderKdB/blame/df0836af38a2b823790b093cda95671fe6a3e6b5/xall/x68/1392-maximize-message-pane/src/scripts/background.js#L198 ...

So I tried binding window.document.getElementById('threadPane').hidden = true, window.gTabmail.currentAbout3Pane.threadTree.toggleAttributes('hidden') and several variations but wasn't quite able to get it to work. Any ideas wildly appreciated..

Oh and there's a MsgToggleThreadPane() in mailnews/content/tabmail.js, any way to invoke that? If it is even relevant.. xD