Your node's icon stays visible — in the app and in the browser tab

Icons are normally authored as a monochrome outline that takes its colour from the surrounding text — stroke="currentColor", the shape nearly every icon set uses. The platform has a rule for exactly that case: an icon with no background of its own gets one generated for it, in a colour derived from the icon itself, with the glyph recoloured white so it reads on a light theme and a dark one alike. An icon that already paints its own background — every store mark, every thread identicon — is left exactly as authored.

The rule ran in one place. Five others drew the icon as it stood:

• the icon tile at the head of every node page,
• the icon beside the title on the overview,
• the icon a node draws when its content refers to itself,
• the preview in the create form,
• and the preview in the icon picker — so the picker showed you something different from what the portal would actually draw.

On the theme the icon was not authored for, it was simply not there. Not a broken-image box, not an error: a blank square. Around twenty nodes of one Space read that way in dark mode, and the only workaround was to re-author every icon by hand with its own background and white detail.

The browser tab, where nothing looked wrong at all

The same icon is lifted into the page head, so a node's own mark shows in the tab strip and in a link preview — and, for Safari (which reads no SVG favicon at all), it is rendered to a PNG by /api/icon/…. Both of those draw the icon on its own, with no page text around it, so an icon whose colour is "whatever the text around me is" has nothing to take a colour from and comes out black. The renderer, meanwhile, deliberately leaves its background transparent — it was written on the understanding that every mark reaching it carries its own.

The result was a black hairline on nothing: invisible in a dark tab strip, invisible on a dark link-preview card, and served as a perfectly valid image, so nothing anywhere reported a problem. Both consumers now receive the icon through the same rule as the app, so the tab, the card and the page cannot disagree about what a node looks like.

What changes for you

If your icons already carry their own background, nothing: the background, the colours and the artwork you authored are left exactly as they are, on every surface. If you re-authored an icon to work around this, it keeps rendering as you wrote it. And an outline icon you had given up on now shows up — on both themes, in the tab, and in a link preview.

Two tests keep it that way, and they are deliberately different in kind: one drives each surface with the icon shape that vanished and reads the markup it produced, and one derives the list of surfaces from the source files rather than from a list someone has to remember to extend — a hand-written list would have named the single surface that was already correct, which is how this went unnoticed in the first place.