为什么更新面板在选择另一个时会取消选择列表框中的当前选择？

I have a asp:ListBox wrapped inside an asp:UpdatePanel. The list box contains all the United States. If I select Alaska, for example, and then scroll down to select Wyoming, the listbox jumps back up to the top of the list instead of staying on Wyoming and it deselects Alaska, but Wyoming remains selected. Has anyone ran into this before?I have a asp:ListBox wrapped inside an asp:Upda