desiger "open file" crashes on kde when qt was compiled without q3 support

It is an issue with midex-up (multiple) qt libs, so low prio (most ppl won't run into this if things are installed properly, plus I could always compile qt with qt3 support, although I don't like the feeling that I'm forced to do so without a good reason... ). Still - maybe it can be easily prevented.

I compile qt without qt3 support, set QTDIR to new install directory, modify path and LD_LIBRARY_PATH in such a way that this new install directory is searched first. When I start new designer, and then try to open file (e.g. click on button "Open..." in the designer's start-up dialog or close this dialog and choose file->open) then I get:

makekdewidgets(4813) fileModule: KFileDialog wasn't able to find 
libkfilemodule:  "Cannot load library /usr/lib64/kde4/libkfilemodule.so:(/usr/lib64/libQt3Support.so.4: 
undefined symbol: _ZN14QObjectPrivate15checkWindowRoleEv)"

[1]+  Segmentation fault      designer

Ofc, /usr/lib64/lib is the old library path.

Maybe it would be possible to modify designer in such a way that if Qt3 support is NOT enabled at the time of compilation then it would use QFileDialog and not KFileDialog even if kdelibs seem to be available? It's a pity to be punished for not using qt3support esp. if this is easily avoidable.

(note that in this setup a newly compiled qtcreator does use qfiledialog if you use file->open while e.g. editing a .pro file; but if you are editing a .ui form [within qtcreator] and then use file->open you get the same crash [I assume thus - coming from designer's code])

I don't need nor want to use qt3support for the software I write. Still, on my system I need to compile qt with q3support or else I won't be able to use designer...