hello! i can't seem to replicate your issue when testing on mobile google chrome but i'm happy to look into it! would it be possible to provide any screenshots / a recording of the issue? feel free to message me on tumblr or upload it here, whichever's more convenient.
Thank you for the quick response. Not sure I can provide a recording, my tablet is pretty old and doesn't have that function. Still, I tried it again this morning. If you tap the menu button;
The Settings screen comes up. There are times when it doesn't come up, if you click slightly above the three bars the menu slides down normally.
If you click slightly below, the Codex appears instead.