How to change the components of Datafilter

[Chandan]

I want the first Combo box , that appears in the data filter , to have ceratin properties like, it must have a scroll drop down. and have the intellisense property, whrein we can put anything in the text box, with auto complete feature. thesefeatures  are possible when i set the properties of combobox item independently. but how to set it for a combobox which is a component of datafilter. i tried the tutorial , but couldnt do it. can someone tell me how to do it.