The sidebar scrolls perfectly fine in Horde 4, and it's gone in Horde 
5 anyway.

I'm currently in the process of migrating my Horde3 applications to 
the Horde4 framework.  One that that I noticed that I had to develop a 
workaround for was that I make heavy use of the sidebar to quickly 
jump to individual games (I know that one user has 50+ nodes under my 
app).  With Horde3, the sidebar was a separate frame with a scrollbar, 
so it wasn't a big deal.  But with Horde4 it is a single div overlay, 
so if the sidebar extends down beyond the rest of the page, you cannot 
access the bottom elements.

I've added some of my own code to add javascript observers to the page 
resize (and trigger that event on dom load) to add CSS max-height and 
overflow-y:auto to the expanded scrollbar, but I'm thinking that this 
should probably be a universal thing in the future.