An owned Window:
Applying the window style Style::Child causes a child window to be created.
When the style Style::Child is not applied, the parent handle is interpreted as the handle of the owner; in which case, an owned window is created.
The presence of the owner window is implicit. The idea of ownership relates to dialog windows. Usually a dialog is a frame window with the desktop as its parent. Despite this, a dialog is required to notify a window of events (usually the window that created it rather than the parent). The owner window is sent notifications, and ownership is specified when a dialog is created. Because dialogs are owned, they are automatically destroyed (dismissed) when the owner window is destroyed.