I created a QtWebEngine instance and set Chromium into debug mode with setting the environment variable QTWEBENGINE_REMOTE_DEBUGGING.

With the debug mode running, I connect to the debug websocket created by Chromium to dispatch debug commands via the ChromeDevTools protocol (see here). With one exception, all comands work. However, when I try to send the command Input.dispatchKeyEvent, the web engine freezes indefinitely. The commands are sent as seen here. The params used with the command have absolutely no effect on the outcome, as long as the command itself is valid.

The thing is, when I try to do the same in the stock Chromium browser, using the same versions as Qt (tested with the Chromium versions of Qt 6.3.1 and 6.2.5), I have zero problems. The problems only shows in combination with the QtWebEngine, that's why I'm filing the bug here.

So maybe there is a bug with how Qt uses Chromium?