Comment # 1 on bug 1034922 from Dr. Werner Fink

From changelog/NEWS

20170401
[...]
  + modify set_curterm() to update ttytype[] data used by longname().
  + modify wattr_set() and wattr_get() to return ERR if win-parameter is
    null, as documented.
  + improve cast used for null-pointer checks in header macros, to
     reduce compiler warnings.
   + modify several functions, using the reserved "opts" parameter to pass
     color- and pair-values larger than 16-bits:
     + getcchar(), setcchar(), slk_attr_set(), vid_puts(), wattr_get(),
       wattr_set(), wchgat(), wcolor_set().
     + Other functions call these with the corresponding altered behavior,
       including chgat(), mvchgat(), mvwchgat(), slk_color_on(),
       slk_color_off(), vid_attr().
[...]

And now compare with libyui-ncurses-2.48.0/src/NCTextPad.cc lines 351-397

[...]

bool NCTextPad::insert( wint_t key )
{
    if ( key == 10 )
    {
        return openLine();
    }

    if ( key < 32 || ( key >= 127 && key < 160 ) || UCHAR_MAX < key )
    {
        return false;
    }

    assertWidth( ++( *cline ) );

    cchar_t cchar;
    attr_t attr;
    short int color;
    wattr_get( w, &attr, &color, NULL ); // NOTE: (w)attr_get is not probided
by NCursesWindow

    wchar_t wch[2];
    wch[0] = key;
    wch[1] = L'\0';

    setcchar( &cchar, wch, attr, color, NULL );
// libncurses6 enables ext_color from struct cchar_t (see curses.h).
// Set ext_color to 0 to respect the settings got from attr_get (bnc#652240).
#ifdef NCURSES_EXT_COLORS
    cchar.ext_color = 0;
#endif
    ins_wch( curs.L, curs.C++, &cchar );

    return true;
}

... AFAICS there is no check if wattr_get() might fail