Edit I have an Asp.Net FormView, with an itemtemplate:
<asp:TemplateField HeaderText="DateStart" SortExpression="DateStart">
<EditItemTemplate>
<asp:TextBox ID="TextBoxEditStageDetailsDateStart" type="datetime-local" runat="server"
Text='<%# Bind("DateStart") %>' CssClass="TextBoxDateTime"></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("DateStart") %>'></asp:Label>
</ItemTemplate>
<ControlStyle Width="160px" />
</asp:TemplateField>
When the Form is in View Mode, the date is correctly showed (of course when the date is set):

However, when the Form change in Edit Mode, the input with type="datetime-local" is showed but is empty, requiring the user to choose a new date. This is the Popup showed:

However, as I can see inspecting the generated html source, the value is correctly set...
<input name="ctl00$MainContent$StageDetailsView$TextBoxEditStageDetailsDateStart" value="28/05/2013 10:00:00" id="MainContent_StageDetailsView_TextBoxEditStageDetailsDateStart" class="TextBoxDateTime" type="datetime-local" style="width:160px;">
So two problems: first is that in Edit mode, I am not able to see what the actual value is; second if I only want to change the day or hour I have to re-enter the whole date...
My question is: Is this the Html5 planned behaviour or I am missing something?