this does not apply to actions that are required to operate the user agent or assistive technology). Success Criterion 2.5.2 Pointer Cancellation Understanding Pointer Cancellation | How to Meet Pointer Cancellation (Level A) 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 . Note 1 Functions that emulate a keyboard or numeric keypad key press are considered essential. Note 2 This requirement applies to web content that interprets pointer actions (i.e. this does not apply to actions that are required to operate the user agent or assistive technology).