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Popup

Popup is an overlay surface used for dropdowns, context menus, and lightweight transient UI.

Popups close when focus is lost or when the user clicks outside (depending on configuration).

Popup

Anchoring

Popups can be positioned relative to:

  • an anchor visual (via Popup.Anchor), or
  • an explicit rectangle in UI coordinates (via Popup.AnchorRect).

AnchorRect is primarily used for point-based popups such as context menus (right-click), where there is no natural anchor visual to align to.

Typical usage

  • Select<T> uses a popup for its dropdown list.
  • ContextMenu uses a popup anchored to the click position.
  • SearchReplacePopup uses a popup-like overlay anchored within an editor.

Focus and dismissal

Popups participate in focus. Common dismissal patterns:

  • close on Escape,
  • close when clicking outside,
  • close when the popup loses focus (for transient UI).

When you show a popup from a control, keep the focus rules explicit: decide whether focus should move into the popup (typical for menus) or remain on the originating control (typical for passive tooltips).

Defaults

  • Default alignment: HorizontalAlignment = Align.Start, VerticalAlignment = Align.Start