using Win32k.sys from 2k3sp2, tooltips show no text anymore

Steps to reproduce:

• undefine the CSR_DBG symbol in https://git.reactos.org/?p=reactos.git;a=blob;f=sdk/include/reactos/subsys/csr/csrsrv.h;hb=0c64ffd3ab82e1980313a9a7cee3ab41595897bf#l13 and rebuild, (I used RosBE2.1.6 gcc dbg lin)
• replace follwing files with their 2k3sp2 version: user32.dll, gdi32.dll, winsrv.dll, win32k.sys, imm32.dll

all tooltips show no content anymore in such a Frankenstein configuration
0.4.13-RC-21-g09d3029_Frankenstein_NoTooltips.png
Nothing gets logged