Pin to Desktop
The Pin to Desktop action allows you keeping a particular window always open on the desktop, denying any attempts of its minimization. The pinned window "sticks" to the desktop surface behind all other windows and can't be minimized in any standard way, including Windows® system commands "Minimize all" (Win+M hotkey) and "Show desktop" (Win+D hotkey). Although you still can hide such window using the alternative minimization.
As a side effect, the pinned window also disappears from the Alt+Tab sequence.
When window is pinned, its window menu is expanded with the extra Pin to desktop item. You can use this item to toggle the "pinned/unpinned" state of this window.
Hint This action can be considered as a permanent "sending-to-bottom"; therefore the Send to bottom action is disabled for windows pinned to desktop. Pinning to desktop is good for background windows that are constantly monitoring some long processes and need to be always open, though behind others.