A Helperbird Feature is Not Supported
One Helperbird feature greyed out with a red badge? Learn what Unavailable means, which features switch off on Google Docs and PDFs, and what to use instead.
On this page5 sections
Helperbird is open and working, but one feature has a small badge beside it and will not turn on. You did nothing wrong. That single feature is switched off for the kind of page you are on.
If nothing in Helperbird works on this page, you have a different problem. Read Why Helperbird (and Other Extensions) Don't Work on Certain Pages.
What Unavailable Means
A small red minus-in-circle means the feature cannot run on this page. Hover over it or focus it with your keyboard to see Unavailable. Select the icon to open a help guide.
Your saved font and spacing settings stay on for supported pages. They are not applied to an unsupported page, and the Text settings running check disappears there. Return to a supported page to use them again.
The Google Workspace banner at the top links to the add-on. The red icon opens help, without opening the add-on modal.
Which Features Switch Off, and Where
These are the features with a page limit. Everything else in Helperbird is not affected by the type of page.
| Feature | Google Docs, Sheets and Slides | PDF in your browser |
|---|---|---|
| Font | Not available | Not available |
| Font size | Not available | Not available |
| Line spacing | Not available | Not available |
| Letter spacing | Not available | Not available |
| Word spacing | Not available | Not available |
| Text alignment | Not available | Not available |
| Highlights | Not available | Not available |
| Highlight Menu | Not available | Available |
| Reading Mode | Available | Not available |
| Immersive Reader | Available | Not available |
| Text to speech | Available, except Google Slides | Available |
Reading Mode also shows Not supported on this page as an error message after you turn it on. That is different: it means Reading Mode could not find an article on the page to strip down.
On Google Docs, Sheets and Slides
For font, size and spacing changes inside Google Docs, Sheets and Slides, use the Helperbird Workspace add-on. See How to Install the Helperbird Google Docs and Slides Add-on.
Google Slides is the exception for Text to speech, because Slides draws a deck in a way Helperbird cannot read. Open the plain text version of the deck and every feature above becomes available: How to Make Google Slides Readable in Helperbird.
On PDFs
In your browser's own PDF viewer, the features that restyle text stay off. Open the PDF in Helperbird's free PDF Reader, where text to speech and text boxes work for free and the advanced highlighting and annotation tools are available with Pro: How to Open the PDF Reader in Helperbird.
Need Additional Help?
If Immersive Reader opens to a blank screen rather than showing a badge, see Why Immersive Reader Does Not Work on Some Websites. Otherwise tell us the site and the feature on our feedback page, or contact Helperbird support.
Printed from the Helperbird Help Center · Updated September 24th, 2026
Questions? We are happy to help — helperbird.com/support