In-Reply-To: <[EMAIL PROTECTED]> I have now had a close look at the much reduced program and I believe that the problem was that I had used sd_setmd in the application hit routine to alter the writing mode to XOR. BUT I had not altered it back to OVER on return from this routine. Having now done so, the problem has gone away. With reference to my earlier message, I suppose that wm_ldraw must somehow do just this.
My thanks to Wolfgang for prodding me to isolate the problem. Christopher Cave
