This issue is observed in machine with the following OS platform (regradless whether the keyboard uses English or German layout):

• Windows
• Linux

Not happening in MAC. Reason being that MAC keyboard has no Windows key.

This issue is also observed in these browsers:

• Chrome
• Firefox
• IE

By right, Windows key should not cause the sidebar to be shown/hidden because '[' is the keyboard shortcut for it.

Here is the screen cast of the issue: http://screencast.com/t/OIf0Oa7OGoQV

Although it is a minor bug but it could be quite annoying for some users.