Shift + ESC is not working

Hi,

the keyboard shortcut Shift + ESC (hide active tool window) is not working. I added a diffrent shortcut (Ctrl + Shift + Alt + Q) and tried it successfully, but I would like to use the original shortcut Shift + ESC. I use IntelliJ Idea 13 on Windows 8.1 x64. Any suggestions?

Thanks in advance,

Michael