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Hand Tremor: When the Pointer Won't Hold Still

Essential tremor is one of the most common movement disorders, and it becomes more common with age. Parkinson's disease, multiple sclerosis, stroke, some medications, cold, fatigue and too much coffee can all make a hand shake. So can a moving bus. On this page your mouse pointer shakes. Every demo uses small, tightly packed targets, drag-only controls or hover menus. Try each task with the tremor on, then turn it off and try again.

WCAG 2.2, Success Criterion 2.5.8 (Target Size (Minimum)), Level AA: The size of the target for pointer inputs is at least 24 by 24 CSS pixels, with some exceptions, for example when a smaller target has enough space around it. Level AAA (2.5.5) asks for 44 by 44.

How the simulation works

You need a mouse or trackpad for this. On a touch screen the simulation has no effect.

Tremor:
Small targets

1. Email toolbar

Task: archive all three emails, one at a time, using the Archive button. Don't delete or report anything.

    The buttons are about 16 pixels tall with 1 pixel between them. Archive sits right next to Delete and Spam, so a small wobble turns a harmless action into a destructive one. Nothing asks you to confirm and there is no undo.
    Small targets

    2. Pizza toppings

    Task: tick exactly Mushrooms, Olives and Peppers.

      Each checkbox is 11 pixels square, and the label text is not connected to it, so clicking the word does nothing. An accidental double click ticks the box and then unticks it straight away. The keyboard does work here, because these are real checkboxes.
      Small targets

      3. Date picker

      Task: choose 14 November 2026.

      November 2026
      Each day is an 18 pixel cell with no gap, so the 13th, 15th, 7th and 21st are all a twitch away. The cells are plain <div>s, so you can't reach them with Tab, and there is no text box to type the date into.
      Dragging

      4. Volume slider

      Task: set the volume to exactly 37.

      80
      You have to grab a 10 pixel handle, hold the button down while moving, and let go at exactly the right moment. The tremor keeps moving the value even while you hold still, and it moves again as you release. There is no keyboard support and no box to type a number. WCAG 2.5.7 (Dragging Movements, Level AA) says anything you can do by dragging must also be possible with a single pointer action, such as clicking.
      Hover menus

      5. Account menu

      Task: Account › Settings › Privacy › Download my data.

      Each submenu opens on hover and closes the instant the pointer leaves, with no delay. You have to follow a narrow path through three levels without the pointer straying by more than a few pixels. The target is right next to "Delete account". The menu can't be opened with a click or the keyboard.
      Timing

      6. Undo

      Task: delete the report, then change your mind and undo it.

      Q3-report.pdf
      File deleted.
      The Undo link is 10 pixel text and disappears after 3 seconds. People with tremor often move more slowly and carefully, so a short time limit and a tiny target together make undo almost impossible. WCAG 2.2.1 (Timing Adjustable, Level A) says users must be able to turn off, adjust or extend time limits.
      The fix

      Big targets, spacing, and more than one way in

      Here are demos 1, 2 and 4 again, rebuilt. Keep the tremor on and try them.

        Volume

        What changed, and what else you can do: