Once reserved, apps must not define a conflicting gesture in the same region

What it is

Once the host OS gives “two fingers down” to the shortcut panel, an app should not hang a same-shaped gesture in that spatial region—not a two-finger pull menu, a two-finger pull search, or a two-finger pull to a homemade drawer. The clash zone is the upper screen and the status band, not the whole canvas. Yielding is a product decision: rebind the command, rather than retune a threshold to race the system.

Why it happens

The system recognizer sees events before the app. Registering the same stroke in the same region yields two outcomes: the app never sees it (system wins), or it sometimes wins at the fringe where the system did not claim, which feels random. People cannot form a stable model. Reservation is a conjunction of space and shape: a two-finger pinch mid-map is usually still legal, because the shape is not “both down.” The ban is that motion cell, not the two-finger channel. It is cousin to “do not occupy three-finger system gestures,” aimed at this pulldown cell.

Studying it

On a device that already reserves the cell, install a same-shaped handler in the app. Count success and ownership from the top band, the upper third, and the lower half. Treat “app succeeded, system panel failed” as a defect even if the app thinks it won—the user lost a system capability. Cover several OS versions; the reserved band moves with edge-to-edge chrome.

Where it stops holding

Platforms that never reserved two-finger pulldown have no such ban. A full-screen game or immersive player that legally hides the status bar may pause the top reservation; it must give it back on exit. Two-finger gestures inside a distinct content control (horizontal table pan) are not the same region. This is regional yield, not the general theory of system-versus-app priority.

Applying it

• Against the target OS gesture table, delete or rebind two-finger pulldown from the top of the app inventory.
• Open homemade drawers with a visible button or a sheet from the bottom, not two fingers from the top.
• Regression: the system panel still opens from a two-finger top pulldown; the app command still has a button. Missing either side occupies the reserved cell.

Related

• Same group: C3.27.1 Two-finger pulldown is reserved by some systems for a shortcut shade · C3.27.2 It collides with two-finger pull-to-refresh and needs count disambiguation · C3.27.4 The panel gesture has almost no visual preview
• Adjacent: C3.31 System versus app gesture priority · C3.12 Three- and four-finger system gestures
• Search: reserved gesture · system shade · gesture exclusion