Dear user Guillaume Blanc, your problem looks like the one we have with 24 bit X-servers. As described in the FAQ, Midas does not support 16 or 24 bit displays. Please, use $ xdpyinfo or $ /midas/99NOVpl2.2/system/idiserv/src/Xtest.exe T to get the setup of your X11 environment. You may have to reinitialize your X-server to 8 or 32 bit displays. Good luck, Klaus Banse