To Disable the Remote Desktop Sharing (RDS) icon's menu, follow the next steps:

1. Open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the regedit utility.
    
2. Expand HKEY_LOCAL_MACHINE\Software\Microsoft\Conferencing\Mcpt (see picture 1).
   
   

   Picture 1

3. Create a new string value (Click on Edit -> New -> String Value).
    
4. Name the value "Nx".
    
5. Double-click on it and set it's value to "1".
    
6. Now the menu options will be grayed out.
    
7. The modifications you made will be in effect after you logout or reboot your PC.