Notepad++: disable enter key for auto-complete

I think this article should help you: http://msdn.microsoft.com/en-us/library/windows/desktop/ee416808(v=vs.85).aspx

If you look at the second example, you will see that it basically gives you what you want. You may put the code that's going to be below (Aside from the WinMain method) in a separate file and have your program call it.

STICKYKEYS g_StartupStickyKeys = {sizeof(STICKYKEYS), 0};
TOGGLEKEYS g_StartupToggleKeys = {sizeof(TOGGLEKEYS), 0};
FILTERKEYS g_StartupFilterKeys = {sizeof(FILTERKEYS), 0};    


INT WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )
{
    // Save the current sticky/toggle/filter key settings so they can be restored them later
    SystemParametersInfo(SPI_GETSTICKYKEYS, sizeof(STICKYKEYS), &g_StartupStickyKeys, 0);
    SystemParametersInfo(SPI_GETTOGGLEKEYS, sizeof(TOGGLEKEYS), &g_StartupToggleKeys, 0);
    SystemParametersInfo(SPI_GETFILTERKEYS, sizeof(FILTERKEYS), &g_StartupFilterKeys, 0);

    // Disable when full screen
    AllowAccessibilityShortcutKeys( false );

    // Restore back when going to windowed or shutting down
    AllowAccessibilityShortcutKeys( true );
}


void AllowAccessibilityShortcutKeys( bool bAllowKeys )
{
    if( bAllowKeys )
    {
        // Restore StickyKeys/etc to original state and enable Windows key      
        STICKYKEYS sk = g_StartupStickyKeys;
        TOGGLEKEYS tk = g_StartupToggleKeys;
        FILTERKEYS fk = g_StartupFilterKeys;

        SystemParametersInfo(SPI_SETSTICKYKEYS, sizeof(STICKYKEYS), &g_StartupStickyKeys, 0);
        SystemParametersInfo(SPI_SETTOGGLEKEYS, sizeof(TOGGLEKEYS), &g_StartupToggleKeys, 0);
        SystemParametersInfo(SPI_SETFILTERKEYS, sizeof(FILTERKEYS), &g_StartupFilterKeys, 0);
    }
    else
    {
        // Disable StickyKeys/etc shortcuts but if the accessibility feature is on, 
        // then leave the settings alone as its probably being usefully used

        STICKYKEYS skOff = g_StartupStickyKeys;
        if( (skOff.dwFlags & SKF_STICKYKEYSON) == 0 )
        {
            // Disable the hotkey and the confirmation
            skOff.dwFlags &= ~SKF_HOTKEYACTIVE;
            skOff.dwFlags &= ~SKF_CONFIRMHOTKEY;

            SystemParametersInfo(SPI_SETSTICKYKEYS, sizeof(STICKYKEYS), &skOff, 0);
        }

        TOGGLEKEYS tkOff = g_StartupToggleKeys;
        if( (tkOff.dwFlags & TKF_TOGGLEKEYSON) == 0 )
        {
            // Disable the hotkey and the confirmation
            tkOff.dwFlags &= ~TKF_HOTKEYACTIVE;
            tkOff.dwFlags &= ~TKF_CONFIRMHOTKEY;

            SystemParametersInfo(SPI_SETTOGGLEKEYS, sizeof(TOGGLEKEYS), &tkOff, 0);
        }

        FILTERKEYS fkOff = g_StartupFilterKeys;
        if( (fkOff.dwFlags & FKF_FILTERKEYSON) == 0 )
        {
            // Disable the hotkey and the confirmation
            fkOff.dwFlags &= ~FKF_HOTKEYACTIVE;
            fkOff.dwFlags &= ~FKF_CONFIRMHOTKEY;

            SystemParametersInfo(SPI_SETFILTERKEYS, sizeof(FILTERKEYS), &fkOff, 0);
        }
    }
}

Hopefully this helps.

This undesired behavior is hard-coded into Scintilla, the text editing component that underlies Notepad++. It can be fixed by removing the following three lines from src/ScintillaBase.cxx:

        case SCI_NEWLINE:
            AutoCompleteCompleted(0, SC_AC_NEWLINE);
            return 0;

With this change, the Enter key no longer commits autocompletion. The Tab key already does that, as noted by user2427906.

It should be possible to download the source code for Notepad++ (which includes Scintilla), make the above change in scintilla\src\ScintillaBase.cxx (the code is slightly different in Notepad++ 6.9, but this shouldn’t be a problem), and then build Notepad++ from the modified source code.

I haven’t tried this because I don’t use Notepad++ nor Windows, but I did the same to Geany—another text editor based on Scintilla—and it seems to work.