>I tried that also, but there is 3500 root nodes and initialization of control is slow (2-3 min with Pentium II on client side).

Just adding 3500 Nodes should take about 3 to 5 seconds on a well running PII.
There must be a few other things slowing your app down <g>.
That said: 3500 Nodes as top level probably isn't the best way to display your data.
How about creating another top level ?
How about splitting the 3500 nodes according to the first letter of the name ?
Adding all the nodes for the largest first letter group should be less than 500 nodes,
since you won't have a uniform distribution. The TV is for structured information -
so give it some structure.

HTH

thomas