Yes, that's the exact same issue I'm running into! Using Alt+Ctrl instead of AltGr does not work either, same as in the issue.

The new editor features in 3.3.1 are delightful! I spend much, much less time tabbing out to Sublime Text since it was introduced. However, there is one nasty problem I've run into: The new editor seems to hate keyboard layouts with an AltGr key, rejecting any inputs made with it. I'm on a Finnish k...

Replacing those DLLs with the Qt 5.3.2 ones did not work for me. Windows 10 x64, Mudlet 3.0.0-delta. Fresh install, default profiles. Replaced Qt DLLs with ones from the ZIP in this thread. Trying open Mudlet gives basically nothing. No indication that it's even trying to load past a quick 'busy' cu...