How to rebuild server-side filtering options

I have a grid. Its data refreshes and changes as the selection changes in a navigating tree.
I use server-side filter in the grid since there are thousands of records for each refresh.

The problem is:
I hope the select filter options change as the data changes, but they never change remaining the same as the first refreshed data.

The grid is created, initted, and attached events only once. But the data is loaded for each time:

mygrid.load('griddata.xml');  // 

And the content of griddata.xml contains the changed options, but it seems never be reloaded by the client, except for the first time.
If the grid is recreated and then loads its data for each refresh, the filter options could be refilled properly.
Is there any solutions that don’t need to create and attach events for each refresh, to refill these filter options?

Thanks in advance.

It is by design, when server side filtering is used, grid parses list of options from the first data loading batch and will not refresh options after that.
There is no public API to change this behavior, the next code uses grid’s internals ( so it can be broken after next update )

grid.attachEvent("onDynXLS", function(){ this._colls_loaded = false; force options reparsing return true; })

Ok, Thanks Stanislav.