@pesterhazy I found out what was going on. The problem was comming from the MaterialUI TextField component that trigger onChange instantly, before the key composition. (I don't know why yet). By setting a :value @my-text-atom the component was re-rendered instantly, breaking the key composition. I found a workaround covering my needs: I assign an :id "my-id", use :defaultValue instead of :value to this TextField and in the onChange handler :

(fn [event new-value]
  (-> (.getElementById js/document "my-id")
       (aset "value" (.. event -target -value)))
  (swap! my-text-atom new-value)) 

@ggaillard the thing to remember is that reagent does some special tricks to make input fields work

one particular problem is that because reagent batches updates, sometimes typing is too slow

that's for controlled components though - by not using value you're using an uncontrolled component, which works differently

anyway, reagent's tricks probably need to be applied to 3rd party input fields, like the one from materialui

one thing that people have tried is to use force-update to make keystrokes be registered immediately

I haven't heard about your particular issue before

it seems weird that keys are registered separately (I guess as unicode composed characters?) - is that on linux?