dhtmlXtree in a Sharepoint site?

Are you aware of customers that have used dhtmlXtree in a Sharepoint site, for site navigation? We are considering this, and while the tree performs fairly well with a local web site, the expand & contract actions seem to lag a lot more when we put the the dhtmlXtree into a Sharepoint page. This web site is hosted in a far-off geographic location, however, I wouldn’t expect server latency to affect the performance of folder expand/collapse. Do you have any insight into what might be causing this and if there are any ways to resolve this?

The problem can be caused by image caching issue , based on server headers, IE can switch in mode, when each image will be downloaded separatly - it can seriously affect performance.
You can try to add next command to tree initialization
which must resolve problems caused by incorrect IE caching.