Slow localized text drawing

[UBoss UBoss]

Hi all,

Using gnustep stable 
    make - 2.0.6
    base -  1.16.3
    gui -  0.14.0
    back - 0.14.0 (Xlib, X11)

OS: solaris 10 

using font Helvetica (included in gnustep)  (iso10646-1 = unicode)

when drawing Loclaized string (Latin2) - [NSString allioc] initWithData: <Latin2 chars as data> encoding:NSISOLatin2StringEcoding]
into textFiled, NSBrowserCell ... 
the responses of application is too slow (about 3-5sec per one nonASCII char)

 after searching in sources found that slow piece of code is  in gui/Sources/NSAttributedString.m 
method 
  fixFontAttributeInRange  
 ....
 on line  ....  subFont = [self _substituteFontFor: uchar font: font];  

returned subFont is nil

after commenting out this line application responses is OK, drawing is OK.

question is why is there substitue if using unicode font ? 

Hope this helps..

UBoss