2.5.2

2.5.2 Pointer Cancellation

WCAG says:

For functionality that can be operated using a single pointer, at least one of the following is true:

No Down-Event: The down-event of the pointer is not used to execute any part of the function;

Abort or Undo: Completion of the function is on the up-event, and a mechanism is available to abort the function before completion or to undo the function after completion;

Up Reversal: The up-event reverses any outcome of the preceding down-event;

Essential: Completing the function on the down-event is essential.

When this is applicable

When there are interactive elements.

Check touching interactive elements

Check twice, once with a mobile touch device, and again with a mouse or trackpad.

Touch or click interactive elements and leave your finger or mouse on it for a few seconds, then move your finger or mouse away and release.

Check:

• nothing happens
• anything that does happen can be cancelled, reverted or removes itself after lifting the finger again

It's not necessary to check every element, check one or two of the same type.

Exceptions

• if whatever happens is part of the operating system, user agent or assistive technology - for example if the browser interferes with anything that is native to the browser, like a context menu
• if not cancelling is essential (like pressing a key on an emulated keyboard)

Other ways to check

For a partial check use the Down-Events auslösen bookmarklet (German language).