Firefox Japanese IME conversion candidate selection interferes with contenteditable selection
OS: macOS 12.0+ · Device: Desktop Any · Browser: Firefox 115.0+ · Keyboard: Japanese (IME)
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Firefox shows different candidate window behavior or conversion latency than Chrome for some Japanese IME backends—handlers tuned on Chromium may mis-handle conversion commits.
Firefox shows different candidate window behavior or conversion latency than Chrome for some Japanese IME backends—handlers tuned on Chromium may mis-handle conversion commits.
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| Case | OS | Device | Browser | Keyboard | Status |
|---|---|---|---|---|---|
| ce-0223-japanese-ime-candidate-firefox | macOS 12.0+ | Desktop Any | Firefox 115.0+ | Japanese (IME) | draft |
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OS: macOS 12.0+ · Device: Desktop Any · Browser: Firefox 115.0+ · Keyboard: Japanese (IME)
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Japanese kanji conversion and Chinese character selection depend on the IME candidate window. Delays, wrong ordering, or Safari-specific lag can cause users to commit the wrong character or see candidates that do not match the underlying buffer—especially under load or in complex layouts.
Many IMEs let users pick candidates with number keys 1–9. In contenteditable, those keys may be consumed by the IME, intercepted by the page for shortcuts, or mis-handled by Safari—causing wrong selection or cancelled composition.
Escape typically cancels IME composition or closes the candidate window. In Edge, Firefox, and other engines, timing and whether partial text remains in the DOM differ—Arabic and Korean IME cases show cross-browser variance.
Moving focus away from the editor while composing text (Chinese, Japanese, Korean) can cancel composition, commit partial text, or leave the IME candidate window out of sync. Safari often shows distinct behavior for Japanese; Chrome behavior for Chinese/Korean is covered in related cases.
During IME composition, keydown often reports keyCode 229 (VK_PROCESSKEY on Windows) for many keys, meaning the event is part of an input method sequence. Enter may commit composition, insert a newline, or be swallowed—Chrome vs Firefox vs Japanese layouts differ. Handlers that assume Enter always means insertParagraph break composition incorrectly.
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