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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsIn Firefox 157, Compact is a supported density setting for Mozilla’s refreshed Nova interface. It makes tabs and toolbar controls smaller so webpages can occupy more of the screen. To enable it, open Settings > Appearance > Window density and select Compact; Firefox saves the change automatically. “Default” means the ordinary spacing when Compact has not been selected.
What Compact and Default density change
Mozilla describes Compact as reducing the size of tabs and toolbar controls, leaving more screen area for webpages. Default is the ordinary spacing when Compact is off. Mozilla does not publish pixel measurements or a complete control-by-control comparison, so there is no supported figure for how much space Compact saves, nor a basis for promising that every part of Nova changes uniformly. Mozilla Support’s Compact mode guidance and its September 29, 2026 design announcement describe the benefit without quantifying it.
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| What you’re comparing | Compact | Default |
|---|---|---|
| Tabs and toolbar controls | Smaller, according to Mozilla’s description of Compact. | Ordinary spacing when Compact has not been selected; Mozilla does not provide a dimensional specification. |
| Webpage area | More of the screen is available to webpages because tabs and toolbar controls take less space. No measured amount is stated. | Less room for webpages than Compact is intended to provide; no measured difference is stated. |
| Where to choose it | In Firefox 157: Settings > Appearance > Window density > Compact. | Leave Compact unselected; Mozilla’s cited instructions do not specify a separate Default-selection procedure. |
How to turn on Compact in Firefox 157
- Open Firefox and select Menu > Settings (or open Settings using your usual method).
- Select Appearance.
- Under Window density, select Compact.
- Close Settings. Mozilla says the change is saved automatically.
Mozilla Support says Compact is directly supported starting with Firefox 157. Mozilla’s September 29, 2026 announcement says the redesigned Firefox is rolling out, while Mozilla’s Add-ons Community Blog identifies Firefox 157 as the Nova release. Rollout timing may mean availability depends on the Firefox version you have installed. Mozilla Add-ons Community Blog
What to do in Firefox 156 or earlier
Mozilla says Compact was removed from the Customize panel in Firefox 89. For versions through Firefox 156, its support instructions describe an about:config workaround, with the choice shown as Compact (not supported). Mozilla warns that changing advanced preferences can affect Firefox’s stability, security, and performance. Proceed only if you understand that warning and follow Mozilla’s instructions carefully.
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- Enter
about:configin the address bar and accept the warning screen. - Find
browser.compactmode.showand set it totrue. - Open Menu > More tools > Customize toolbar.
- Open the Density menu and choose Compact (not supported).
- Select Done to leave toolbar customization.
These legacy steps are Mozilla’s workaround for older versions, not the supported settings path in Firefox 157. See Mozilla’s full Compact mode instructions and warning before changing the advanced preference.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Nova, themes, and what the comparison cannot establish
Nova is Mozilla’s name for the refreshed Firefox interface. The Compact setting is a density choice within Firefox, rather than a separate interface or a return to an earlier Firefox release. Mozilla’s Add-ons Community Blog advises theme authors to check themes under Compact density, but that is not a guarantee that every theme or interface element will render identically. Mozilla’s cited public materials do not provide an exhaustive comparison across operating systems, themes, or every Nova component.
Mozilla Bugzilla issue 2023631 contains development discussion about density options and prior user choices; it is implementation context, not a final end-user specification. Proposed details in a development issue should not be treated as a promise about current behavior. Mozilla Bugzilla issue 2023631
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- Product Identifiers ISBN-10 0385073534 ISBN-13 9780385073530
- Key Details Author Inc. Staff Foxfire Fund Number Of Pages 384 pages
- Series Foxfire Format Paperback Publication Date 1972-02-17 Language English Publisher Knopf Doubleday Publishing Group
- Additional Details Copyright Date 1972 Illustrated Yes
- Dimensions Weight 18.6 Oz Height 1 In. Width 6 In. Length 9.2 In.
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