Tab order – Failed

Tab order – Failed is a result from the Accessibility Checker in Adobe Acrobat Pro. It means one or more pages don't tell PDF readers to move through links and form fields in the order of the document's structure, its tags. When that happens, pressing the Tab key can jump around the page instead of following the text. Acrobat lists the rule in its Page Content category, and it's one of the easiest failures to fix.

What this means

Every PDF page has a tab order setting that controls the order in which the Tab key moves through links, form fields and other annotations:

• Use Row Order: across each row, from top to bottom.
• Use Column Order: down each column, from left to right.
• Use Document Structure: follows the tags, which is the same order a screen reader uses.
• Unspecified: left to the PDF reader, which often means the order the items were added to the page.

Adobe's help explains that because people often use Tab to move through a PDF, the tab order needs to follow the document structure. Acrobat's rule passes when pages use Use Document Structure, and PDF/UA, the ISO standard for accessible PDFs, requires that setting on every page that has links, fields or other annotations.

There's one catch. Use Document Structure only helps if the tags themselves are in the right order. If the reading order is wrong, keyboard focus will follow the wrong order faithfully. Fix the setting and check the order of the tags.

Why it matters

People who use a keyboard instead of a mouse, screen reader users and people who use switch devices move from link to link and field to field with Tab. When the order jumps, a form can become very hard to fill in: focus might move from "First name" to "Signature" and back to "Last name". This is covered by WCAG 2.1 success criteria 2.4.3 Focus Order and 2.1.1 Keyboard.

How to fix it in Acrobat Pro

If you add links or form fields to the file later, set the tab order again for the pages you changed.

Fix it in the source file

Most authoring apps don't let you choose this page setting directly, so it's usually set in the PDF. What you can control in the source is the reading order, which the tab order will follow:

• Word: build the document with styles, keep pictures In Line with Text, and avoid floating text boxes, so the exported tags come out in the order people read.
• PowerPoint: check the order of objects on each slide in the Reading Order pane (Review > Check Accessibility > Reading Order Pane on Windows).
• Forms built in Acrobat: add fields in the order people will fill them in, and tag them next to their labels.

After any change to links or fields in Acrobat, run the check again.

Fix it automatically with Includoc

Includoc fixes this automatically. We set every page that has links or form fields to follow the structure order.

Because the structure order is only as good as the reading order, we also set a column-aware reading order and our AI pass checks it page by page. You confirm the order on the review screen, where every page shows its reading order as numbered blocks that you can rearrange with drag and drop or the keyboard.

Standards

Related errors

• Widget annotations in Form tag: fields need to be in the structure before the tab order can follow it.
• Logical Reading Order – Needs manual check: the order of the tags, which the tab order follows.

For forms in particular, read Forms in PDFs, or check a PDF free to find pages with the wrong tab order.