There's a problem with radSearchbox inserted in a radWindow contenttemplate.
On First show then inputText width is equal to 0 until a contextitem is selected or a button pushed . (test on ie10 firefox and chrome)
code example :
<telerik:RadWindow runat="server" ID="RadWindow1" Modal="true" AutoSize="true"
Behaviors="Close,Move">
<ContentTemplate>
<telerik:RadSearchBox ID="RadSearchBox1" runat="server" Width="350" SearchContext-ShowDefaultItem="False"
OnClientSearch="onClientSearch" OnClientButtonCommand="onClientButtonCommand"
ShowSearchButton="false" Skin="Default">
<DropDownSettings Height="150" Width="300" />
<Localization LoadingItemsMessage="recherche en cours....." DefaultItemText="Saisissez le nom du point ici" />
<WebServiceSettings Path="PointDeTournee.aspx" Method="GetResults" />
<SearchContext>
<Items>
<telerik:SearchContextItem Text="POI" Key="1" ImageUrl="../Img/POI/Special_Divers-Bl.bmp" Selected="true"/>
<telerik:SearchContextItem Text="PA" Key="2" ImageUrl="../Img/POI/PA.bmp" />
</Items>
</SearchContext>
</telerik:RadSearchBox>
</ContentTemplate>
</telerik:RadWindow>