I think this is due to the BufferView pointer cached in LyXText. It could explain many other reported crash... I'm on it.
You must still be working on it, just let you know that I get compiling errors as of r15591. g++ -o debug/common/frontends/qt4/QLPainter.o -c -g -O -DQT_SHARED -DHAVE_CONFIG_H -DQT_CLEAN_NAMESPACE -DQT_GENUINE_STR -DQT_NO_STL -DQT_NO_KEYWORDS -DQT_GUI_LIB -Idebug/common -Isrc -Isrc -Iboost -Idebug/intl -I/home/bpeng/lyx-devel/qt4/include -I/home/bpeng/lyx-devel/qt4/include -I/home/bpeng/lyx-devel/qt4/include/QtCore -I/home/bpeng/lyx-devel/qt4/include/QtGui -Idebug/common/images -Isrc/images -Idebug/common/frontends -Isrc/frontends -Idebug/common/frontends/qt4 -Isrc/frontends/qt4 -Idebug/common/frontends/controllers -Isrc/frontends/controllers src/frontends/qt4/QLPainter.C src/frontends/qt4/QLPainter.C: In constructor `lyx::frontend::QLPainter::QLPainter(QWidget*)':src/frontends/qt4/QLPainter.C:39: error: no matching function for call to `lyx::frontend::QLPainter::begin(QWidget*&)' /home/bpeng/lyx-devel/qt4/include/QtGui/qpainter.h:78: note: candidates are: bool QPainter::begin(QPaintDevice*) scons: *** [debug/common/frontends/qt4/QLPainter.o] Error 1
