Guard (filter, event)
A filter that covers its child with a striped shadow. On the
first click, the guard is removed, exposing and activating the child.
If the mouse moves out of the guarded area, the guard returns.
- Behavior
- On down-click, the shadow becomes recessed; restores the
raised shadow on up-click or chord-abort, and generates an event if
the mouse is still within the button on the up-click.
- Shape
- The shape of its child plus the shadow.
- Notes
- A guard is often used around a component whose action has has
potentially serious side-effects; e.g., (Button
"Delete"), (Boolean "Override").