Thai Font Vowel issue on WinCE

Hi im using QT 5.2.1 on Windows CE and i'm having this issue with Thai fonts (see issue1.png).

I found the following bug report at 

https://bugreports.qt.io/browse/QTBUG-33071?jql=text%20~%20%22thai%22 

I have applied this fix mentioned there in the

  QWindowsFontEngine::boundingBox(glyph_t glyph, const QTransform &t);

function and i get the following (issue2.png).

At this point i have no clue on how to adjust this so the characters go down.

I tried to increase the y value, but it seems that at some point the characters disappear, which leaves me to believe the top symbols (vowels i think) are actually printed on a different line??

I have little experience with fonts and i do not speak Thai,, any help would be greatly appreciated.

PS: the issue seems to be in 

qtbase/src/plugins/platforms/windows/qwindowsfontengine.cpp

in the QWindowsFontEngine::boundingBox(glyph_t glyph, const QTransform &t); function.

I have added the specific file to attachments as well, in case you cannot find it.