Locking assertion failure.  Backtrace:
#0 /usr/lib/libxcb-xlib.so.0 [0xb6b4a767]
#1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_lock+0x2e) [0xb6b4a81e]
#2 /usr/lib/libX11.so.6 [0xb7708648]
#3 /usr/lib/libX11.so.6(XGetGeometry+0x25) [0xb76e6475]
#4 /usr/lib/libmred-360.so [0xb7af1ada]
#5 /usr/lib/libX11.so.6(XCheckIfEvent+0x7e) [0xb76dd0be]
#6 /usr/lib/libmred-360.so(_Z16MrEdGetNextEventiiP7_XEventPP11MrEdContext+0x97) [0xb7af1895]
#7 /usr/lib/libmred-360.so [0xb7af035d]
#8 /usr/lib/libmzscheme-360.so(scheme_thread_block+0x31b) [0xb7eedcab]
#9 /usr/lib/libmzscheme-360.so(scheme_block_until+0x14f) [0xb7eee22e]
#10 /usr/lib/libmred-360.so [0xb7aef722]
#11 /usr/lib/libmred-360.so(_Z29wxDispatchEventsUntilWaitablePFiPvES_P13Scheme_Object+0xa8) [0xb7aefa28]
#12 /usr/lib/libmred-360.so(_Z20mred_wait_eventspacev+0x56) [0xb7aefc5c]
#13 /usr/bin/mred [0x8049644]
#14 /usr/bin/mred [0x8049a24]
#15 /usr/bin/mred [0x8049a5d]
#16 /usr/lib/libmred-360.so(_ZN7MrEdApp8RealInitEv+0x3f) [0xb7aeda03]
#17 /usr/lib/libmred-360.so [0xb7af05ce]
#18 /usr/lib/libmzscheme-360.so(scheme_do_eval+0x194a) [0xb7dedbf3]
#19 /usr/lib/libmzscheme-360.so [0xb7e00051]
mred: xcb_xlib.c:73: xcb_xlib_lock: Assertion `!c->xlib.lock' failed.
Aborted (core dumped)