Why is spell-check underlining inconsistent in Edit PDF Mode?

Question

Hi everyone,

I’m using Adobe Acrobat Pro (2026) on Windows 11, and I’m seeing inconsistent spelling‑check behavior in the new Acrobat interface.

While in Edit PDF mode, inside an active text box, Acrobat did underline a misspelled word in red the other day, and it even did so earlier today. However, after closing and reopening the same file, the misspelled word is no longer underlined.

If I type inside the text box, the misspelled word does get a red underline, but only while I’m actively typing. Once I click out of the text box or reopen the file, the underline disappears. Previously, Acrobat showed the red underline without requiring me to type a word in the text box.

I understand that Acrobat’s spell check is primarily intended for Comments, but I believed that while editing text in Edit PDF, Acrobat would still flag misspellings with a red underline. Since I’ve seen this behavior before, I’m trying to understand why it’s no longer consistent.

Is this expected behavior in the new Acrobat, or is something causing spell‑check to stop recognizing text in Edit mode? Would you please explain how the red underline behavior works in both Edit Mode and Comments?

Amal Jaiswal · Answer

​Hi @HappyTeacher_63,Hope you are doing well, and thanks for the detailed write-up.Acrobat's built-in spell checker is designed to work only on comments, form fields, and editable text added through tools like Edit PDF or Fill & Sign. For more information, please check the help pageCheck spellings and manage custom dictionaries in AcrobatWithin that scope, though, there's an important distinction between the two behaviors you described:Red underline while actively typing: this is live, real-time checking. It only exists while Acrobat is tracking your active cursor in that text run.Underline persists after you click out or reopen the file: this doesn't happen, by design. The live underline isn't saved into the PDF as a markup; it's a temporary overlay tied to the active editing session. Once you click away or close and reopen the file, there's nothing stored to redraw, so it disappears until you're actively editing that text again.That matches what you're seeing now. What doesn't quite match is your memory of it flagging existing misspellings just from opening the text box, without you needing to type. That's worth double-checking. One setting: Go to Preferences (Ctrl,Cmd+K) > Spelling and make sure "Check spelling while typing" is enabled, and let us know how it goes.Also, share your exact build number (Help > About Adobe Acrobat). If the preference is already on and it's still behaving inconsistently, please share a small video recording of the steps you are taking and the issue as it occurs for more clarity and further investigation.~Amal

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