Android Chrome: Emoji insertion cancels composition without committing

Phenomenon

A data-loss bug exists in high-version Chromium for Android (131+) when mixing complex IME composition with emoji input. If a user is in the middle of typing a character (especially in CJK or Thai) and switches to the emoji keyboard to insert an icon, the browser triggers a compositionend event with data: "" or null. This effectively wipes out the currently composing character instead of finalizing it.

Reproduction Steps

1. Open a contenteditable editor on Android.
2. Use a CJK IME (like Korean Gboard).
3. Type a character so that the underline is visible (active composition).
4. Without hitting Space or Enter, open the Emoji menu and select an emoji.
5. Check if the composing character remains in the DOM.

Observed Behavior

• Buffer Wipeout: The compositionupdate text disappears from the DOM.
• Missing Events: The browser fails to send an insertReplacementText or insertText event for the ghost-character.
• Inconsistent ‘beforeinput’: beforeinput types for the emoji are fired, but no events are fired to “clean up” the previous session.

Impact

• Information Loss: Users lose the last syllable of their sentence if they punctuate with an emoji.
• Frustration: Users must switch back keyboards, re-type the character, and then re-add the emoji.

Browser Comparison

• Chrome for Android (131+): Confirmed regression.
• iOS Safari: Correctly flushes the composition buffer before inserting the emoji.
• Firefox for Android: Generally stable; correctly handles the keyboard switch.

References & Solutions

Mitigation: manual flush

Developers can watch for a keyboard type change (if detectable) or manually capture the last compositionupdate value. If a focus-like or input-mode change occurs while isComposing is true, manually insert the cached text.

• Chromium Issue #381254331: Emoji picker cancels composition