The AttachmentTRStyle is not working for me

    <CuteWebUI:UploadAttachments runat="server" ID="UploadAttachments1" ManualStartUpload="true" 
          NumFilesShowCancelAll="1000" InsertText="Upload Statements" MultipleFilesUpload="true"
        TempDirectory="~/Uploads" Visible="True" FileTooLargeMsg="This file is too large. Files must be less than 2GB"
    onuploadcompleted="UploadAttachments1_UploadCompleted" UploadType="HTML5" 

AttachmentTRStyle="background-color:#999999;
 >
        <InsertButtonStyle Width="100" />
        <ValidateOption MaxSizeKB="2001100" />
    </CuteWebUI:UploadAttachments>
 

Every time I pick a file, the background color stays white 

I have a grid of alternating white and gray rows. 

Is there some other property I need to set ?