IME doesn't switch input mode when leaving focus on input field

To reproduce the issue,

1. click on google's input search field
2. turn on IME
3. type in some text
4. click out of input field

Expect:

input method changes,  (tested in firefox)

Actual:

input method doesn't change (tested in qupzilla and qutebrowser)

Here are two screencast for illustration:

This is the expected behavior in firefox

https://la.wentropy.com/wOHV.webm

This is the issue in qupzilla

https://la.wentropy.com/_ez5.webm

Notice the up right tray indicating the IME state.

> Why does this matter?

If the IME state keeps active after leaving the input field, it will block all the hotkeys. And I cannot turn it off. I have to enter some input field again and trigger the disable IME hotkey.