Ajax calendar (always transparent background)

Question

I have a problem with the Ajax calendar background, I can’t remove the transparent background, the shortcut under the calendar holder appears through the calendar I'm trying to do the following, but nothing helps

• change EnableEventValidation
• put calendar in div with white background
• change Z-Index to the maximum value
• make css class for calendar. An expander with all the necessary value, but BackGround has no effect.

• check web.config file

  <pages enableEventValidation="true"> <controls> <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/> </controls> </pages> 

• check if the following script exists in the page source:

   <script src="/AJAXTimer/ScriptResource.axd?d=9tk5luWIQHpRBi2jvaLA3ovu_ryV3iBlv84cuaA3MT--_ e3q9KdLubgmmRoMp9ixegSpkyQ0LFGM_KxDw2qwSneq8GS2D1TcTOujL7Q85DE1&amp;t=556b0a58" type="text/javascript"></script> 

Any ideas on this issue?