Version:            (using KDE 4.2.4)
OS:                Linux
Installed from:    Debian testing/unstable Packages

How to reproduce the crash (100% of the time on my machine):
- Open the "Add plasmoid" dialog box ;
- On the bottom, choose "Download new plasmoids" from the "Install new plasmoids" menu. It opens the "Get Hot New Stuff" window ;
- Switch to the "Add plasmoid" dialog box, using alt+tab or the mouse and close it (Close button on bottom or X button on top right) ;
- Close the "Get Hot New Stuff" window and voilà, segfault.

Expected behaviour : 
Maybe KDE should not allow the "Add plasmoid" window to be closed while the "Get Hot New Stuff" window is open, and/or plasma shouldn't crash when the window is closed...

Loaded plugins (not sure about the name, i only know the french ones) :
Desktop manager ;
App launcher ;
New peripherial notificator ;
Digital clock ;
Miniature box.

Backtrace of the crash:
Application : Espace de travail Plasma (plasma), signal SIGSEGV
0xb7dce2fc in nanosleep () from /lib/libc.so.6
[Current thread is 0 (LWP 4693)]

Thread 4 (Thread 0xa95d7b90 (LWP 4700)):
#0  0xb4f818d0 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0xb7e0f7bd in pthread_cond_wait () from /lib/libc.so.6
#2  0xb6755822 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#3  0xb522bfd2 in ?? () from /usr/lib/libQtNetwork.so.4
#4  0xb675480e in ?? () from /usr/lib/libQtCore.so.4
#5  0xb4f7df50 in start_thread () from /lib/libpthread.so.0
#6  0xb7e0369e in clone () from /lib/libc.so.6

Thread 3 (Thread 0xa8daeb90 (LWP 4701)):
#0  0xb4f818d0 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0xb7e0f7bd in pthread_cond_wait () from /lib/libc.so.6
#2  0xb6755822 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#3  0xa9601c2a in ?? () from /usr/lib/kde4/plasma_wallpaper_image.so
#4  0x0a34b5a0 in ?? ()
#5  0x0a34b59c in ?? ()
#6  0xffffffff in ?? ()
#7  0xa8dae230 in ?? ()
#8  0xa8dae2f0 in ?? ()
#9  0xa9607540 in ?? () from /usr/lib/kde4/plasma_wallpaper_image.so
#10 0xb793d8a8 in vtable for KSvgRenderer () from /usr/lib/libkdeui.so.5
#11 0xa9607636 in ?? () from /usr/lib/kde4/plasma_wallpaper_image.so
#12 0xb7da587f in posix_memalign () from /lib/libc.so.6
#13 0xb675480e in ?? () from /usr/lib/libQtCore.so.4
#14 0xb4f7df50 in start_thread () from /lib/libpthread.so.0
#15 0xb7e0369e in clone () from /lib/libc.so.6

Thread 2 (Thread 0xa84a2b90 (LWP 4754)):
#0  0xb4f81be8 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0xb7e0f814 in pthread_cond_timedwait () from /lib/libc.so.6
#2  0xb67557fc in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#3  0xb674adb6 in ?? () from /usr/lib/libQtCore.so.4
#4  0xb675480e in ?? () from /usr/lib/libQtCore.so.4
#5  0xb4f7df50 in start_thread () from /lib/libpthread.so.0
#6  0xb7e0369e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb4ba9710 (LWP 4693)):
#0  0xb7dce2fc in nanosleep () from /lib/libc.so.6
#1  0xb7dce11f in sleep () from /lib/libc.so.6
#2  0xb780b0f8 in ?? () from /usr/lib/libkdeui.so.5
#3  0x00000000 in ?? ()