add: bPtr->dimage = NULL;
context: WMSetButtonImage(WMButton *bPtr, WMPixmap *image){    if (bPtr->image!=NULL)	WMReleasePixmap(bPtr->image);    bPtr->image = WMRetainPixmap(image);    if (bPtr->dimage) {	bPtr->dimage->pixmap = None;	WMReleasePixmap(bPtr->dimage);    }    if (image) {	bPtr->dimage = WMCreatePixmapFromXPixmaps(WMWidgetScreen(bPtr), 						  image->pixmap, None,						  image->width, image->height,						  image->depth);	updateDisabledMask(bPtr);    }    if (bPtr->view->flags.realized) {	paintButton(bPtr);    }}