Grab

This capability documents one focused aspect of the widget interface (Tk/Tcl-style behavior + bootstack extensions).

Note: You typically won’t use bootstack.core.capabilities.grab directly. This page describes the behavior that widgets expose.

Pointer/keyboard grab helpers (grab).

A grab confines mouse and keyboard events to a particular widget subtree.

When a grab is active

Pointer events are delivered only to the grab window and its descendants.
Keyboard events are also directed to the grab window (effectively focusing input).
This is the foundation for modal interactions (e.g., modal dialogs).

Tk supports two kinds of grabs

Local (application) grab: confines events within the current Tk application.
Global grab: confines events at the window system level (more intrusive).

Notes

Grabs should be released when you are done (typically in a finally: block).
Global grabs can make the entire desktop feel “stuck” if misused; prefer local grabs unless you specifically need global behavior.
A grab does not automatically make a window modal; typical modal patterns also: transient(parent), focus_set(), and wait_window() / wait_visibility().

grab_set() -> None

Set a local (application) grab on this widget.

With a local grab, events are confined within the current Tk application. This is the preferred grab type for modal dialogs inside an application.

grab_set_global() -> None

Set a global grab on this widget.

A global grab confines events at the window system level. This is more intrusive than a local grab and should be used with care.

grab_release() -> None

Release a grab held by this widget (if any).

grab_current() -> Any

Return the widget in this application that currently holds the grab.

Returns:

Type	Description
`Any`	The widget instance that currently holds the grab, or None if no grab is held by this application.

grab_status() -> str | None

Return the grab status for this widget.

Returns:

Type	Description
`str \| None`	The grab status: "local" if this widget holds a local grab, "global" if this widget holds a global grab, or None if this widget does not hold the grab.