Patch slightly modified and committed.

Changes have been made in Git for this ticket:

Bug #8989: Fix folder list scrolling.
Signed-off-by: Michael M Slusarz <slusarz@curecanti.org>

http://git.horde.org/diff.php/horde/js/dragdrop2.js?rt=horde-git&r1=35115b66c5d4d2309553647f475724ab58f9f8b5&r2=0736b67c4a6869d1e1452f2f025ac03ec176f4ea

The following small patch does the job for me.
I have 150 folders and everything works as expected using Firefox.

If I understood correctly;
p[1] seems to be the size of the folder tree (folders that are 
expanded) * some value (probably font height)
p[3] = p[1] + dim.height

I've noticed that when dealing with lots of folder, p[1] is always 
bigger than window.innerHeight and that probably why it was always 
scrolling back to the first folder of the tree.


--- dragdrop2.js.org        2010-05-24 16:33:50.000000000 +0200
+++ dragdrop2.js        2010-05-24 16:34:37.000000000 +0200
@@ -626,16 +626,16 @@
          //    speed[0] = this.lastCoord[0] - p[0];
          //}
          // Top scroll
-        if (this.lastCoord[1] < p[1]) {
-            speed[1] = this.lastCoord[1] - p[1];
+        if (this.lastCoord[1] <(window.innerHeight - dim.height)) {
+            speed[1] = this.lastCoord[1] - (window.innerHeight - dim.height);
          }
          // Scroll right
          //if (this.lastCoord[0] > p[2]) {
          //    speed[0] = this.lastCoord[0] - p[2];
          //}
          // Scroll left
-        if (this.lastCoord[1] > p[3]) {
-            speed[1] = this.lastCoord[1] - p[3];
+        if (this.lastCoord[1] > (window.innerHeight - 10)) {
+            speed[1] = this.lastCoord[1] - (window.innerHeight - 10);
          }

          if (speed[0] || speed[1]) {

Definitely looks more like a browser/OS/UI bug than an issue with the 
JS code.  (For the record, I tested with FF 3.6 on Ubuntu and WinXP).

Going to mark as not a bug.  If you can provide further debug 
information, we will reopen this ticket.

I don't see any error in apache/horde logs file.
Firebug seems to be happy and horde caches are disabled.
Firefox's cache was cleared as well as user's prefs.

I'll see if I can find something but I doubt it.

For further debugging information, please read the 'AJAX 
Troubleshooting' section in imp/docs/INSTALL.

Works for me.

Firefox 3.5.9 and 3.6.3

I can't drag and drop a message to any of the last folders. when 
dragging the message, the folder list automatically scroll back up to 
the beginning of the folder list.

The attached video will probably explain better.