The following code uses UpdatePanel and maintains treeview state.
As you can see there are two buttons
one is in UpdatePanel
second is out of UpdatePanel
ExpandLevel=\"2\" BorderColor=\"Silver\" BorderWidth=\"1px\" Height=\"330px\" Width=\"260px\"
Padding=\"2px\" FadeEffect=\"true\" DisplayBar=\"true\" BarBackgroundImage=\"$bar_grey\">
BarImageUrl=\"$office2003_delete\">
Value=\"Inbox\" ToolTip=\"3 item(s) unread\">
Value=\"John Smith\">
Value=\"Search Folders\" BarImageUrl=\"$office2003_flag_red\" CanBeSelected=\"False\">
RowHeight=\"16px\" Padding=\"1px;4px;4px;1px\" />
BorderWidth=\"1px\" ForeColor=\"White\" Padding=\"0px;3px;3px;0px\" />
The treeview saves state as it should.
Could you please provide an example that will cause the error and that we can debug locally.
Thanks.