SVG 2 lets a textPath href point at a basic shape as well as a path: "An URL reference to the path element or basic shape element onto which the glyphs will be rendered" (https://w3c.github.io/svgwg/svg2-draft/text.html#TextPathElementHrefAttribute). WebKit lays the text out on the shape the first time. After that, changing the shape does not move the text. A path target does follow. Test case: a text with <textPath href="#s">, where #s is a rect, circle, ellipse, line or polygon. After the first layout, move the shape (for example rect y from 20 to 120), then read getStartPositionOfChar(3). path (control): y 100 -> 150, follows rect, circle, ellipse, line, polygon: unchanged Cause: SVGTextPathElement::buildPendingResource() calls addReferencingElement() only when the target is an SVGPathElement (SVGTextPathElement.cpp:180), and SVGPathElement::invalidatePathDependencies() is what tells the textPath. RenderSVGTextPath::layoutPath() already accepts any SVGGeometryElement. Other engines, same probe: * Firefox 160 follows all six. * Chrome Canary 158 never puts the text on the shape (position (0,0) before any edit): Blink's LayoutSVGTextPath::LayoutPath() only accepts an SVGPathElement. That is a separate gap, not this bug. I will add more WPT. Probe attached.