Under the hood
New 'Raster' UI element added with a cap on total cells per tree
What
Claude Code's internal validator for custom terminal UI layouts (used to check dialogs and similar UI before they render) now recognizes a Raster element type with columns and rows properties. It enforces a maximum on the total number of cells (columns times rows) across all Raster elements in a single UI tree, and rejects the tree if that limit is exceeded.
Why
This adds a new building block for grid-like terminal UI while guarding against layouts large enough to cause performance or rendering problems.