ibus input doesn't work on AppImage

I've seen many other appimages that doesn't work with ibus. But some projects seem to have found some way to make it work.

Steps to reproduce

• Make sure ibus is configured with the expected languages (example)
• Make sure ibus-daemon is running or tray icon showing (if not, run ibus-daemon -xdr)
• Run Librewolf appimage (if already running, close and rerun because ibus doesn't work on apps opened before running the daemon)
• Press the ibus key combination to switch layouts
• Try to type in that language

Current behavior

Inputs English characters. Although it types in that language just fine on other apps (e.g. leafpad, LXTerminal).

Expected behavior

Input characters from selected ibus layout.