rem: if (!validOpenFile(panel)) return;
context: buttonClick(WMButton *bPtr, WMFilePanel *panel){    if (bPtr == panel->okButton) {	if (panel->flags.fileMustExist) {	    char *file;	    if (!validOpenFile(panel))		return;	    	    file = getCurrentFileName(panel);	    if (access(file, F_OK)!=0) {		WMRunAlertPanel(WMWidgetScreen(panel->win), panel->win,				"Error", "File does not exist.",				"Ok", NULL, NULL);		free(file);		return;	    }	    free(file);	}	panel->flags.canceled = 0;    } else	panel->flags.canceled = 1;    panel->flags.done = 1;}