Set activeCodePage to UTF-8 in the Notepad3.exe.manifest file.

[geniuszxy]

Fix #5963

Referring to zufuliu#168, sometimes StrTrimA() cannot handle some UTF-8 strings correctly, so I changed the code to directly check the last two chars.

I have found another way to solve this issue without touching code, referring to Use UTF-8 code pages in Windows apps, so that ANSI APIs can also handle UTF-8 strings correctly.

[hpwamr]

Hello @geniuszxy ,
Using Notepad3 (x64) 7.26.715.1 beta, I can't reproduce issue #5963. 🤔
I'm not sure if this PR is necessary. 🤔

[hpwamr]

Again, I can't reproduce your issue... 🔍 🤔

I'm using Notepad3 (x64) 7.26.715.1 beta

You can find this beta version here: #1129
Could you please try with this Notepad3Portable_7.26.715.1_beta.paf.exe portable (PAF) version "out off the box" (keep the original settings)?

[geniuszxy]

Yes, I can reproduce this issue using the PAF version you provided. This is a video record:

2026-08-14.23-05-03.mp4

[geniuszxy]

I did some research on this, and as I mentioned, it seems to be related to the version of Windows.

I am using Windows 10 22H2, and the version of the kernelbase.dll is 10.0.19041.6280. I decompiled the CharNextA function using IDA, and the result is:

//KernelBase.10.0.19041.6280
LPSTR __stdcall CharNextA(LPCSTR lpsz)
{
  int v2; // eax
  LPSTR result; // rax

  if ( (unsigned __int8)IsMBToWCSExtPresent() )
    v2 = CheckDBCSEnabledExt();
  else
    v2 = NlsMbCodePageTag;
  if ( v2 && IsDBCSLeadByte(*lpsz) )
    ++lpsz;
  result = (LPSTR)(lpsz + 1);
  if ( !*lpsz )
    return (LPSTR)lpsz;
  return result;
}

I guess this IsDBCSLeadByte function here is used to determine if the previous character is >127, and if it is, the next character will also be included.

Therefore, strings like ホ\r\n (\xe3\x83\x9b\x0d\x0a) will be split into 3 characters: \xe3\x83 \x9b\x0d \x0a.

And I downloaded another kernelbase.dll with version 10.0.26100.8972 online, the decompilation result of its CharNextA function is:

//KernelBase.10.0.26100.8972
LPSTR __stdcall CharNextA(LPCSTR lpsz)
{
  int v2; // eax
  LPSTR result; // rax
  __int64 v4; // rcx

  if ( (unsigned __int8)IsMBToWCSExtPresent() )
    v2 = CheckDBCSEnabledExt();
  else
    v2 = NlsMbCodePageTag;
  if ( !v2 || gAnsiCodePage == 65001 )
  {
LABEL_4:
    result = (LPSTR)(lpsz + 1);
    if ( !*lpsz )
      return (LPSTR)lpsz;
    return result;
  }
  if ( gpACPHashN )
  {
    v4 = *(_QWORD *)(gpACPHashN + 48);
    if ( v4 && *(_WORD *)(v4 + 2i64 * *(unsigned __int8 *)lpsz) )
      ++lpsz;
    goto LABEL_4;
  }
  SetLastError_0(2u);
  result = (LPSTR)(lpsz + 1);
  if ( !*lpsz )
    return (LPSTR)lpsz;
  return result;
}

From the condition of gAnsiCodePage == 65001, it can be seen that this version only counts one character for UTF-8 code page.

[geniuszxy]

Hi @hpwamr, have you enabled "Beta: Use Unicode UTF-8 for worldwide language support" in the locale settings? This setting can solve my issue, but it can also corrupt other softwares.