Auto-scroll when dragging to an edge

What it is

Drag auto-scroll moves content when a dragged object reaches the edge of a scrollable container, exposing off-screen destinations. It extends drag reach without requiring people to drop, scroll, and pick up the object again.

Why it happens

The system treats edge entry or dwell as a signal to continue transport, using edge distance, dwell time, or pointer speed to set scroll rate. Content coordinates move while the pointer stays on screen, so people maintain pressure, judge speed, and search for new targets simultaneously. Excess speed passes targets; insufficient speed makes long drags tiring.

Studying it

Manipulate activation zone, delay, speed curve, container length, and target distance. Record success, overscrolling, reverse correction, dwell, and cancellation. Test nested containers and multi-column lists to determine which layer scrolls.

Where it stops holding

Auto-scroll does not fit every drag: canvases, maps, and edge toolbars may assign other meanings to the edge. Touch edges also conflict with system navigation. For short content or obvious scrollbars, it can add accidental movement without benefit.

Applying it

• Enable it only during active drag when more content really exists, showing direction and speed change clearly.
• Use progressive speed and cancellable dwell rather than immediate high-speed jumps.
• Test long lists, nested containers, and system-edge gestures, logging overscroll and wrong drops.

Related

• Same group: C1.08.1 Drag and drop has three phases: pickup, transport, and drop · C1.08.2 Drag-start thresholds prevent a click from becoming a drag · C1.08.3 Valid drop targets must be explicit during drag · C1.08.5 Drag and drop can be cancelled and returned to origin · C1.08.6 Drag and drop needs a non-drag equivalent
• Nearby: C1.03 Control-display gain · G1 Navigation and information architecture
• Search terms: drag auto-scroll · edge scrolling · scrolling during drag