Invalid char is inserted with Mention plugin in Japanese environment

[higty]

📝 Provide detailed reproduction steps (if any)

Hi. I use CKEditor with mention plugin. CKEditor Language setting is English.
editor.create(document.getElementById("RichTextbox"), { language: "en", //other property... }

When I input Japanese character, it show below.

After mention inserted, I stroked keyboard like this.
T A N A K A Space Enter

In Japanese, space key is a trigger to translate KANA to Kanji.

✔️ Expected result

田中
"T" is not inserted before "田中".

❌ Actual result

t田中
"T" is inserted before "田中".

📃 Other details

• Browser: …chrome latest
• OS: …Windows 10
• CKEditor version: …18.0.0
• Installed CKEditor plugins: …Mention

[Reinmar]

The way I test it:

1. I have my default keyboard layout (PL) first.
2. I insert a mention.
3. I switch to Japanese (e.g. Katakana).
4. I type "tanaka".
5. The first letter of that word ("t") is excluded from IME.

If you try that without the steps 1-2. then "t" is included.

@higty, did I get this right?

[higty]

If I input 3-5 then 田中 is inserted without problem.
The actual key stroke is below with empty CKEditor.
"@" --Mention list show in my setting
"Up" --selecting mention
"Enter" --mention selected
"Change IME"
"t"
"a"

t is inserted.

[higty]

Another investigation of this is here.

"@" --Mention list show in my setting
"Up" --selecting mention
"Enter" --mention selected
"Backspace" --delete space just after mention.
"Space" --insert space after mention
"Change IME"
"t"
"a"

This will not insert t after mention. The space automatically inserted after selecting mention may cause problem.

[higty]

Hi.

Does this issue have any progress?

[higty]

Hi. @Reinmar
Does this issue have any progress?

[higty]

@Reinmar
Is there any pregress??