Introduce InputMethod to flake.
Qt allows you to enter text using X11's compose or things like chinese and it will then offer an QInputEvent to the widget. Which has to be shipped to the tool so it can respond properly.

This code allows us to handle input method events as well as provide a default implementation which maps them to keyevents (meaning all tools will automatically work).
TODO; alter the rest of the canvasses to forward the event and to do a setAttribute(Qt::WA_InputMethodEnabled, true);