windowsover

Windowsover is a concept in graphical user interface design referring to overlays that render content above one or more application windows without permanently altering their z-order. They are used to present transient information, controls, or guidance while allowing users to return quickly to the underlying context.

A windowsover overlay is typically drawn on a dedicated overlay layer or as a high-priority top-level surface that composes with the normal window stack. It may be translucent or opaque, and is usually dismissible by user action, automatic timeout, or context exit. Accessibility considerations include ensuring that focus and screen reader semantics follow the overlay while it is visible.

Variants of windowsover include modal overlays that block interaction with underlying content until dismissed, and non-modal overlays that permit continued interaction. Overlays may be anchored to a specific window or appear as floating panels centered on the screen. Performance and input handling are key concerns, particularly in systems with many windows or hardware-accelerated compositing.

Examples include in-app tutorials, contextual help balloons, notification banners, and system-wide prompts. The concept is supported to varying degrees by modern window managers on major platforms, but there is no universal standard for implementation.

See also: overlay, z-order, GUI, window manager, compositor. References: [citation needed].