Hello! I wrote an application with matplotlib, which often (3 times a second or more) updates the graphics window. When I switch off the update, the aplication is quite stable, but with updates Xlib prints the following lines and the application freezes. Xlib: unexpected async reply (sequence 0x1318f)! Xlib: sequence lost (0x20000 > 0x1318f) in reply type 0x0! I do not know how to debug/backtrace this message. Does anyone have a clue? The application is using matplotlib with pygtk and numarray, running under Debian testing. python-matplotlib-data 0.86.2-4 python-matplotlib-doc 0.86.2-4 python2.4-matplotlib 0.86.2-4 python2.4-gtk2 2.8.2-3 libcairo2 1.0.4-1+b1 libcairo2-dev 1.0.4-1+b1 python2.4-cairo 1.0.2-1 It is not clear to me, if this error is caused by matplotlib, but it seems to be "correlated" to its use. Any help is welcome. Thanks, achim