don't mix personal canvas and multi-canvas modes

src/mod/applications/mod_conference/mod_conference.c

@@ -3125,6 +3125,11 @@ conference_obj_t *conference_new(char *name, conference_xml_cfg_t cfg, switch_co
 
 	if (video_canvas_count < 1) video_canvas_count = 1;
 
+	if (conference_utils_test_flag(conference, CFLAG_PERSONAL_CANVAS) && video_canvas_count) {
+		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "Personal Canvas and Multi-Canvas modes are not compatable. 1 canvas will be used.\n");
+		video_canvas_count = 1;
+	}
+
 	if (conference->conference_video_mode == CONF_VIDEO_MODE_MUX) {
 		video_layout_t *vlayout = conference_video_get_layout(conference, conference->video_layout_name, conference->video_layout_group);