An XML state texture on an instance over a template went through the Lua path leg, which reuses the populated region, so the template's TexCoords, size, tint, blend and anchors stayed on the new art.
In 1.12.1 `Button::LoadXML` (`0x7788c0`) builds a fresh region for each state tag through the `<Layers>` adder (`0x6f26f0`) and hands it to the slot store (`0x778fd0`, `0x779110`; the checked pair `0x785330`, `0x785440`), which destroys the region it held. A fresh region has TexCoords 0..1 and BLEND (`0x76fc40`, `0x76fc64`), and an XML highlight keeps its own blend (`0x7789a4`).
The XML leg now builds the region as a `<Layers>` texture and installs it, freeing the old one; the Lua leg is unchanged. An XML highlight with no `alphaMode` now draws BLEND.
Tests: all six tags on a CheckButton template, the name kept, the Lua leg's region kept.
Fixes#875🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
