using trunk (r1085248)

How to reproduce:
- Expand the local folders,
- Click on a folder which contains messages (eg 'inbox', I also reproduced with the trash folder),
- In the folder list, click on an empty area, the message list is then empty (I'm not sure that's the expected behavior),
- Click back on the previous folder, KMail crashes.

BT:

Application: KMail (kmail), signal: Segmentation fault
[Current thread is 1 (Thread 0xb17bb760 (LWP 15355))]

Thread 2 (Thread 0xafe31b70 (LWP 15360)):
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb5892d95 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb5d4227c in pthread_cond_wait () from /lib/libc.so.6
#3  0xb396d947 in ?? () from /usr/lib/libQtWebKit.so.4
#4  0xb396d98f in ?? () from /usr/lib/libQtWebKit.so.4
#5  0xb588e6e5 in start_thread () from /lib/libpthread.so.0
#6  0xb588e600 in ?? () from /lib/libpthread.so.0

Thread 1 (Thread 0xb17bb760 (LWP 15355)):
[KCrash Handler]
#6  0xb5348a6b in MessageList::Core::Item::date (this=0x8781120) at /kde/src/KDE/kdepim/messagelist/core/item.cpp:449
#7  0xb5365e92 in MessageList::Core::ModelPrivate::viewItemJobStepInternalForJobPass1Fill (this=0x83a2000, job=0x870f268, tStart=...) at /kde/src/KDE/kdepim/messagelist/core/model.cpp:2703
#8  0xb5367bb1 in MessageList::Core::ModelPrivate::viewItemJobStepInternalForJob (this=0x83a2000, job=0x870f268, tStart=...) at /kde/src/KDE/kdepim/messagelist/core/model.cpp:3326
#9  0xb536a3d1 in MessageList::Core::ModelPrivate::viewItemJobStepInternal (this=0x83a2000) at /kde/src/KDE/kdepim/messagelist/core/model.cpp:3713
#10 0xb536ae6d in MessageList::Core::ModelPrivate::viewItemJobStep (this=0x83a2000) at /kde/src/KDE/kdepim/messagelist/core/model.cpp:3928
#11 0xb536d08d in MessageList::Core::Model::qt_metacall (this=0x838a8b0, _c=InvokeMetaMethod, _id=2, _a=0xbfa7e6cc) at /kde/build/KDE/kdepim/messagelist/model.moc:90
#12 0xb6043f0d in QMetaObject::metacall (object=0x838a8b0, cl=141523044, idx=26, argv=0xbfa7e6cc) at kernel/qmetaobject.cpp:237
#13 0xb6052d3a in QMetaObject::activate (sender=0x83a201c, m=0xb61555a4, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3285
#14 0xb60a6165 in QTimer::timeout (this=0x83a201c) at .moc/release-shared/moc_qtimer.cpp:134
#15 0xb605b096 in QTimer::timerEvent (this=0x83a201c, e=0xbfa7ec24) at kernel/qtimer.cpp:271
#16 0xb604f844 in QObject::event (this=0x83a201c, e=0x87023c4) at kernel/qobject.cpp:1204
#17 0xb628a82c in QApplicationPrivate::notify_helper (this=0x8084e20, receiver=0x83a201c, e=0xbfa7ec24) at kernel/qapplication.cpp:4300
#18 0xb6291678 in QApplication::notify (this=0xbfa7ef98, receiver=0x83a201c, e=0xbfa7ec24) at kernel/qapplication.cpp:4183
#19 0xb76938b1 in KApplication::notify (this=0xbfa7ef98, receiver=0x83a201c, event=0xbfa7ec24) at /usr/src/debug/kdelibs-4.4.62svn1084462/kdeui/kernel/kapplication.cpp:302
#20 0xb603eb9e in QCoreApplication::notifyInternal (this=0xbfa7ef98, receiver=0x83a201c, event=0xbfa7ec24) at kernel/qcoreapplication.cpp:704
#21 0xb606ed8e in sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:215
#22 QTimerInfoList::activateTimers (event=<value optimized out>, receiver=<value optimized out>) at kernel/qeventdispatcher_unix.cpp:617
#23 0xb606f48f in QEventDispatcherUNIX::processEvents (this=0x8058a68, flags=) at kernel/qeventdispatcher_unix.cpp:938
#24 0xb634baea in QEventDispatcherX11::processEvents (this=0x8058a68, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#25 0xb603d20d in QEventLoop::processEvents (this=0xbfa7ee94, flags=) at kernel/qeventloop.cpp:149
#26 0xb603d659 in QEventLoop::exec (this=0xbfa7ee94, flags=...) at kernel/qeventloop.cpp:201
#27 0xb60417d0 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#28 0xb628a8d4 in QApplication::exec () at kernel/qapplication.cpp:3579
#29 0x0804b1ba in main (argc=1, argv=0xbfa7f0b4) at /kde/src/KDE/kdepim/kmail/main.cpp:154

Console log:

kmail(15355) KWebPage::acceptNavigationRequest: url:   QUrl( "file:///home/krop" )  , type:  5 , frame:  QWebFrame(0x8297a88)
kmail(15355)/kio (AccessManager) KIO::AccessManager::createRequest: GetOperation:  QUrl( "file:///home/krop" )               
kmail(15355)/kio (Scheduler) KIO::SchedulerPrivate::doJob: KIO::SimpleJob(0x8484a98)                                         
kmail(15355)/kio (Scheduler) KIO::SchedulerPrivate::scheduleJob: KIO::TransferJob(0x8484a98)                                 
kmail(15355)/kio (Scheduler) KIO::SchedulerPrivate::setJobPriority: KIO::TransferJob(0x8484a98) 1                            
kmail(15355)/kio (Scheduler) KIO::SchedulerPrivate::cancelJob: KIO::TransferJob(0x8484a98) QObject(0x0)                      
kmail(15355)/kio (Scheduler) KIO::SchedulerPrivate::jobFinished: KIO::TransferJob(0x8484a98) QObject(0x0)                    
kmail(15355) KMMainWidget::updateMessageActions: Fix enable/disable send_queued action                                       
kmail(15355) MessageList::Core::View::resizeEvent: Resize event enter (viewport width is  1313 )                             
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Finished filling the view with 40 messages                    
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: That took 659 msecs inside the model and 659 in total.        
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: 100 percent of the time was spent in the model.               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time for layoutChanged(), in msecs: 0 ( 0 percent )           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time to expand tree, in msecs: 0 ( 0 percent )                
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in the model: 60.698            
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in total: 60.698                
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of threads: 37                                         
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of groups: 8                                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages per thread: 1.08108                                  
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Threads per group: 4.625                                      
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages with the same subject: Max: 3 Avg: 1                 
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Now follows a breakdown of the jobs.                          
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ----------------------------------------------                
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Job 1 ( Creating items from messages and simple threading )   
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Share of complete time: 100 percent                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time in msecs: 659                                            
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of elements: 40                                        
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Elements per second: 60.698                                   
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of chunks: 1                                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ==========================================================    
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Finished filling the view with 0 messages                     
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: That took 9 msecs inside the model and 980 in total.          
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: 0.918367 percent of the time was spent in the model.          
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time for layoutChanged(), in msecs: 0 ( 0 percent )           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time to expand tree, in msecs: 0 ( 0 percent )                
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in the model: 0                 
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in total: 0                     
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of threads: 37                                         
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of groups: 8                                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages per thread: 0                                        
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Threads per group: 4.625                                      
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages with the same subject: Max: 3 Avg: 1                 
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Now follows a breakdown of the jobs.                          
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ----------------------------------------------                
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Job 3 ( Updating messages )                                   
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Share of complete time: 100 percent                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time in msecs: 9                                              
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of elements: 40                                        
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Elements per second: 4444.44                                  
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of chunks: 1                                           
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:                                                               
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ==========================================================    

kmail(15355) MessageList::Core::View::resizeEvent: Resize event enter (viewport width is  1313 )
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Finished filling the view with 0 messages
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: That took 2 msecs inside the model and 26037 in total.
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: 0.00768138 percent of the time was spent in the model.
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time for layoutChanged(), in msecs: 0 ( 0 percent )
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time to expand tree, in msecs: 0 ( 0 percent )
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in the model: 0
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of messages per second in total: 0
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of threads: 0
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of groups: 0
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages per thread: nan
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Threads per group: nan
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Messages with the same subject: Max: 0 Avg: -2147483648
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Now follows a breakdown of the jobs.
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ----------------------------------------------
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Job 2 ( Removing messages )
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Share of complete time: 100 percent
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Time in msecs: 2
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of elements: 40
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Elements per second: 20000
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: Number of chunks: 1
kmail(15355) MessageList::Core::ModelPrivate::printStatistics:
kmail(15355) MessageList::Core::ModelPrivate::printStatistics: ==========================================================
kmail(15355) MessageList::Core::View::resizeEvent: Resize event enter (viewport width is  1313 )
*** KMail got signal 11 (Crashing)