setString selection fix

AppKit/CPTextView/CPTextView.j

@@ -478,6 +478,7 @@ var kDelegateRespondsTo_textShouldBeginEditing
 - (void)setString:(CPString)aString
 {
     [_textStorage replaceCharactersInRange:CPMakeRange(0, [_layoutManager numberOfCharacters]) withString:aString];
+    [self setSelectedRange:CPMakeRange(0, [aString length])];
     [self didChangeText];
     [_layoutManager _validateLayoutAndGlyphs];
     [self sizeToFit];