Possible Server Side Sorting/Filtering bug

I am using dhtmlxgrid connector with server side sorting & filtering.

Below is the snippet of code:

$gridconn = new GridConnector($conn);
$gridconn->enable_log("temp.log",true);
$config = new GridConfiguration();
$config->setHeader("City");
$config->attachHeader("#connector_text_filter");
$config->setColSorting("connector");
$config->setColTypes("ro");
$gridconn->set_config($config);
$gridconn->dynamic_loading(50);
$gridconn->render_table("citytable","id","cityvalues");

There is some interesting quirk i noticed.

When i try to type in the filter … it DOES NOT work. i.e no values are filtered. But i know the SELECT command is run on server side based on temp.log file.

However, when i Sort, Sorting works just fine.
But once i sort, ONLY THEN magically the server side filtering functionality starts working as well!

What can be the cause (and solution)!?

Thanks.

Can you provide a snippet of js code, which you are using on client side to init the grid?
Server side code looks valid, and must not cause any issues on its own.