O que você está procurando é DesktopCoral :
DesktopCoral is an unusual program designed to "reserve" some portion of your desktop which is shielded from maximized applications..
Essentially, it acts like an invisible resizeable docking bar, which can be docked to any side of your desktop. This invisible dock acts as a barrier to maximized applications and essentially shields this area of your desktop from other applications.
Within this shielded area you might put certain application windows that you want to be always visible, or you might put one of the many desktop tools like a calendar or system information component.