Work around for when thread_next points to a nonexistant message.

web/root/sajax-forum/message_display.xjs

@@ -38,6 +38,7 @@ if(new_stats[msg_number].inherit_new)
 					var saved_msg_number;
 					var hdr;
 					var last_good_message=msg_number;
+					var last_next=0;
 
 					msg_number=headers[top_msg].thread_first;
 					while(msg_number && msg_number != top_msg) {
@@ -60,8 +61,9 @@ if(new_stats[msg_number].inherit_new)
 							//}
 						}
 
-						if(hdr.thread_next) {
+						if(hdr.thread_next && hdr.thread_next != last_next) {
 							msg_number=hdr.thread_next;
+							last_next=msg_number;
 							moved_back=false;
 							continue;
 						}

web/root/sajax-forum/messages.xjs

@@ -99,7 +99,7 @@ else {
 				continue;
 			}
 		}
-		if(hdr.thread_next)
+		if(hdr.thread_next && these_headers[msg_number]==undefined)
 			msg_number=hdr.thread_next;
 		else
 			msg_number=hdr.thread_back;
@@ -126,6 +126,7 @@ for(i in top_level) {
 	if(headers[top_msg].when_imported_time > last_mod_time)
 		last_mod_time=headers[top_msg].when_imported_time;
 	var last_good_message=top_msg;
+	var last_next=0;
 
 	msg_number=headers[top_msg].thread_first;
 	while(msg_number && msg_number != top_msg) {
@@ -168,7 +169,8 @@ for(i in top_level) {
 				continue;
 			}
 		}
-		if(hdr.thread_next) {
+		if(hdr.thread_next && hdr.thread_next != last_next) {
+			last_next=hdr.thread_next;
 			msg_number=hdr.thread_next;
 			moved_back=false;
 			continue;