This has been an error I had hoped was fixed in the latest release, but it still remains. It only happens in IE6, which I now see that MSDN has IE6 VPCs, so I am hoping the toolkit team can reproduce this bug. I have attached the code below. Please note there is no codebehind. The bug is the "flashing" or repainting that IE6 does when the page loads. Simply put this in an ASPX page and run in IE6. You can refresh the page again to see it happen. All of the drop downs will repaint and the headers will adjust slightly. It does not do this in IE7.
Work item: http://www.codeplex.com/AtlasControlToolkit/WorkItem/View.aspx?WorkItemId=6312 (I meant to create it as high, but missed it on save).
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
<style>
div.collapsePanelHeader{
color: Black;
background: #eeeeee;
background-repeat:repeat-x;
font-weight:bold;
}
div.collapsePanel
{
overflow:hidden;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<ajax:ScriptManager ID="scriptmanager" runat="server" />
<!-- panels -->
<asp:Panel ID="CommonFieldsHeader" runat="server" CssClass="collapsePanelHeader" Height="20px">
<div style="padding: 5px; cursor: pointer; vertical-align: middle;">
<div style="float: left;">
Initial Report</div>
<div style="float: left; margin-left: 20px;">
<asp:Label ID="CommonFieldsLabel" runat="server">(Hide Details...)</asp:Label></div>
</div>
</asp:Panel>
<asp:Panel ID="CommonFieldsPanel" runat="server" CssClass="collapsePanel">
<table border="0">
<tr>
<td>label</td>
<td><asp:DropDownList ID="test1" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList1" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList2" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList3" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList4" runat="server" /></td>
</tr>
</table>
</asp:Panel>
<asp:Panel ID="FormSpecificHeader" runat="server" CssClass="collapsePanelHeader" Height="20px">
<div style="padding: 5px; cursor: pointer; vertical-align: middle;">
<div style="float: left;">
Incident Details</div>
<div style="float: left; margin-left: 20px;">
<asp:Label ID="FormSpecificLabel" runat="server">(Hide Details...)</asp:Label></div>
</div>
</asp:Panel>
<asp:Panel ID="FormSpecificPanel" runat="server" CssClass="collapsePanel">
<table border="0">
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList5" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList6" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList7" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList8" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList9" runat="server" /></td>
</tr>
</table>
</asp:Panel>
<asp:Panel ID="SummaryHeader" runat="server" CssClass="collapsePanelHeader" Height="20px">
<div style="padding: 5px; cursor: pointer; vertical-align: middle;">
<div style="float: left;">
Summary</div>
<div style="float: left; margin-left: 20px;">
<asp:Label ID="SummaryLabel" runat="server">(Show Details...)</asp:Label></div>
</div>
</asp:Panel>
<asp:Panel ID="SummaryPanel" runat="server" CssClass="collapsePanel" Height="0">
<table border="0">
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList10" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList11" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList12" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList13" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList14" runat="server" /></td>
</tr>
</table>
</asp:Panel>
<asp:Panel ID="CommentsHeader" runat="server" CssClass="collapsePanelHeader" Height="20px">
<div style="padding: 5px; cursor: pointer; vertical-align: middle;">
<div style="float: left;">
Comments</div>
<div style="float: left; margin-left: 20px;">
<asp:Label ID="CommentsLabel" runat="server">(Show Details...)</asp:Label></div>
</div>
</asp:Panel>
<asp:Panel ID="CommentsPanel" runat="server" CssClass="collapsePanel" Height="0">
<table border="0">
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList15" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList16" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList17" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList18" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList19" runat="server" /></td>
</tr>
</table>
</asp:Panel>
<asp:Panel ID="HistoryHeader" runat="server" CssClass="collapsePanelHeader" Height="20px">
<div style="padding: 5px; cursor: pointer; vertical-align: middle;">
<div style="float: left;">
Edit History</div>
<div style="float: left; margin-left: 20px;">
<asp:Label ID="HistoryLabel" runat="server">(Show Details...)</asp:Label></div>
</div>
</asp:Panel>
<asp:Panel ID="HistoryPanel" runat="server" CssClass="collapsePanel" Height="0">
<table border="0">
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList20" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList21" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList22" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList23" runat="server" /></td>
</tr>
<tr>
<td>label</td>
<td><asp:DropDownList ID="DropDownList24" runat="server" /></td>
</tr>
</table>
</asp:Panel>
<!-- end panels -->
<ajaxToolkit:CollapsiblePanelExtender ID="CommonExt" runat="server" TargetControlID="CommonFieldsPanel" ExpandControlID="CommonFieldsHeader" CollapseControlID="CommonFieldsHeader" Collapsed="False" TextLabelID="CommonFieldsLabel" ExpandedText="(Hide Details...)" CollapsedText="(Show Details...)" ImageControlID="CommonFieldsImage" SuppressPostBack="true" />
<ajaxToolkit:CollapsiblePanelExtender ID="FormExt" runat="server" TargetControlID="FormSpecificPanel" ExpandControlID="FormSpecificHeader" CollapseControlID="FormSpecificHeader" Collapsed="False" TextLabelID="FormSpecificLabel" ExpandedText="(Hide Details...)" CollapsedText="(Show Details...)" ImageControlID="FormSpecificImage" SuppressPostBack="true" />
<ajaxToolkit:CollapsiblePanelExtender ID="SummaryExt" runat="server" TargetControlID="SummaryPanel" ExpandControlID="SummaryHeader" CollapseControlID="SummaryHeader" Collapsed="True" TextLabelID="SummaryLabel" ExpandedText="(Hide Details...)" CollapsedText="(Show Details...)" ImageControlID="SummaryImage" SuppressPostBack="true" />
<ajaxToolkit:CollapsiblePanelExtender ID="HistoryExt" runat="server" TargetControlID="HistoryPanel" ExpandControlID="HistoryHeader" CollapseControlID="HistoryHeader" Collapsed="True" TextLabelID="HistoryLabel" ExpandedText="(Hide Details...)" CollapsedText="(Show Details...)" ImageControlID="HistoryImage" SuppressPostBack="true" />
<ajaxToolkit:CollapsiblePanelExtender ID="CommentsExt" runat="server" TargetControlID="CommentsPanel" ExpandControlID="CommentsHeader" CollapseControlID="CommentsHeader" Collapsed="True" TextLabelID="CommentsLabel" ExpandedText="(Hide Details...)" CollapsedText="(Show Details...)" ImageControlID="CommentsImage" SuppressPostBack="true" />
</form>
</body>
</html>