[BUG] Cannot use Vietnamese Character in first character of text line

[huyhandes]

Describe the bug
The first character auto disappeard when type the Vietnamese text.

To Reproduce
Steps to reproduce the behavior:
0. Install any Vietnamese unicode app like: EVkey, JOKey, GoTiengViet, etc... and switch to Vietnamese mode

1. Go to any chat
2. Click on type message
3. Type any text with unicode character like: Đ(DD), á(as), ơ(ow)
4. The text disappeared

Expected behavior
Well worked text as above

Desktop (please complete the following information):

• OS: OSX 13.6.5
• Browser: Rambox
• Version WebK 2.1.0 (499)

Additional context
This problem happen on many browsers and OSs. I think it's the Webk version problem. This issue not happen on WebA version.

[specialgift45]

I had the same issue as above
By typing the first character that had Vietnamese diacritics, the input content would disappear.
This issue has been happening for months now.

[NotEvenANeko]

Same issue here.
The input disappears if the first character is a Chinese character.
And on my testing it only occurs on Chromium-based browsers (Edge 125 and Chrome 126), it won't happen on Firefox.

[NotEvenANeko]

Seems like the document.execCommand API has a weird implementation on Chromium-based browsers, so Web K mitigates it by resetting the textContent to empty string of the input element.

But if I input something with IME or external app on Chromium-based browsers, an input event with empty value is triggered just between typing and entering the final word, causing the resetting procedure triggered, and the input words are removed.