Comment 23 for bug 284546

The problem as I see it running OSX 10.8.5 is triggered whenever the pressure sensitivity is enabled. Before that the pen could be used to create calligraphic lines. Here is a trace:

NU gdb 6.3.50-20050815 (Apple version gdb-1824) (Wed Feb 6 22:51:23 UTC 2013)
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This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared libraries ........ done

(gdb) run inkscape
Starting program: /Applications/Inkscape.app/Contents/MacOS/Inkscape inkscape
Reading symbols for shared libraries +++++++......................................................................................................................................... done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries . done
Reading symbols for shared libraries ........ done
Reading symbols for shared libraries . done
Reading symbols for shared libraries .. done
Warning: AppleCollationOrder setting not found, using AppleLocale.
Setting Language: .UTF-8

(process:50639): Gtk-WARNING **: Locale not supported by C library.
 Using the fallback 'C' locale.
/Users/alejandro/.inkscape-etc/gtkrc:56: Clearlooks configuration option "menuitemstyle" is not supported and will be ignored.
/Users/alejandro/.inkscape-etc/gtkrc:57: Clearlooks configuration option "listviewitemstyle" is not supported and will be ignored.
/Users/alejandro/.inkscape-etc/gtkrc:58: Clearlooks configuration option "progressbarstyle" is not supported and will be ignored.

(inkscape-bin:50639): Gtk-WARNING **: Could not find the icon 'object-visible'. The 'hicolor' theme
was not found either, perhaps you need to install it.
You can get a copy from:
 http://icon-theme.freedesktop.org/releases
libc++abi.dylib: terminate called throwing an exception

Emergency save activated!

Emergency save document locations:
  /Users/alejandro/New document 1.2013_12_02_13_44_55.0.svg
Emergency save completed. Inkscape will close now.
If you can reproduce this crash, please file a bug at www.inkscape.org
with a detailed description of the steps leading to the crash, so we can fix it.

Program received signal SIGINT, Interrupt.
0x95b937ce in mach_msg_trap ()
(gdb) bt
#0 0x95b937ce in mach_msg_trap ()
#1 0x95b92cac in mach_msg ()
#2 0x97094f79 in __CFRunLoopServiceMachPort ()
#3 0x9709a95f in __CFRunLoopRun ()
#4 0x9709a01a in CFRunLoopRunSpecific ()
#5 0x97099e8b in CFRunLoopRunInMode ()
#6 0x91606f5a in RunCurrentEventLoopInMode ()
#7 0x91606cc9 in ReceiveNextEventCommon ()
#8 0x9176c1ad in _AcquireNextEvent ()
#9 0x9175af6a in RunApplicationEventLoop ()
#10 0x00002b9e in main ()