I've experienced the same thing.
I've had the same thing but involving the taskbar too, I find that a good way to solve it is to delete the shortcut from the Start Menu/Taskbar or desktop and right click > new shortcut, and then create a new one, the icon then usually comes back. This must be fixed in the RTM though because I've been having none of the same issues. 
Hope this helps, Jack
Operating System Windows 7 Ultimate (x64) or Mac OS X Lion
Computer Type MacBook Pro (Late 2011)
OS Service Pack SP1
Internet Explorer Version 9
CPU Type and Speed Intel Core i5 (2.3 GHz)
System Memory Type 4GB DDR3
Hard Drive 250GB 5200RPM
Printer Epson Stylus SX535WD
Gaming Console Xbox 360
Anti-virus Software Microsoft Security Essentials
Productivity Suite Office 2010 / Office for Mac 2011 / iWork '09
System Install Date 06.09.2011
Computer Skill Level Self-Taught Expert
Windows Experience Index 5.1
Favorite Game Minecraft
Favorite Application Google Chrome