I have a dynamically populated ComponentArt:ComboBox with Autopostback property set to true. So every time the selection changes, a postback to server would be fired. Everything seems to work fine except that the lists of all available items are also posted back to the server.

from Firebug:

ComboBox1_Data  %3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3E150%20Mile%20House%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAach%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAachen%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAaheim%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAakrehamn%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAalbeke%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAalen%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAalst%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAalter%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3E%C3%84%C3%A4nekoski%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarau%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarberg%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarbergen%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarburg%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarebakken%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarschot%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAarsele%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAartrijke%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAartselaar%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3Cc%3E%3Cr%3E%3Cc%3E%3Cr%3E%3Cc%3EText%3C%2Fc%3E%3Cc%3EAavasaksa%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E%3C%2Fc%3E%3C%2Fr%3E
ComboBox1_Input Aalst
ComboBox1_SelectedIndex 7

As most my clients are using slow connections, this amount of postback has a huge impact on their user experience. Since I'm storing the viewstates in session already, there's really no need for any of the component to restore states from the client. So I'm wondering if this is normal for ComponentArt:ComboBox to do this and not other controls, or this is the normal way of doing things?