RequireFieldValidator firing too quick when click on the calendar instead of the save button

 HI,
I got a requiredfieldvalidator for a date/calendar textbox. When the user clicks on the calendar, the validation rule are quickly fired off. I need the validation to be fired off when the user click on the save button. Any help is appreaciated.
<td align="right"><span class="fieldHeading">Received By: </span></td><td> <asp:DropDownList ID="ddlInsertReceivedBy" runat="server" SelectedValue="<%# BindItem.CASES.FOIA_CASES.RECEIVED_BY %>" SelectMethod="GetReceivedBys" ItemType="OFAC.FOIA.BusinessEntities.NHObjects.OFAC_LOOKUP" DataTextField="DESCRIPTION" DataValueField="LOOKUP_UID" AppendDataBoundItems="true"><asp:ListItem Text="[Select]" Value=""></asp:ListItem></asp:DropDownList>&nbsp;<span class="req ...