Ok, I found the bug.

If I have something like this:

<div id=DivTitleShortEnglish runat=server visible=false>
<tr> 
<TD Class=Label><asp:Label ID="LabelTitleShortEnglish" runat="server"></asp:Label>:</td>
<td><img src="Images/point.gif" width=3 height=1 /></td>
<td><asp:textbox ID="TitleShort_E" runat="server" Width=300></asp:textbox>
</tr>
</div>

This makes the textbox control to be recognized as a generic control.

If I have something like this:

<tr> 
<TD Class=Label><asp:Label ID="LabelTitleShortEnglish" runat="server"></asp:Label>:</td>
<td><img src="Images/point.gif" width=3 height=1 /></td>
<td><asp:textbox ID="TitleShort_E" runat="server" Width=300></asp:textbox>
</tr>

This is ok.

So, once encapsulated inside a div, all other controls are recognized ok. But, the textbox control is recognized as a generic control.

Anyone has that link again to report that bug to Microsoft? This was working before. So, it is obviously something recent.