What
Plugins can draw boxes on screen and give them a borderStyle. Claude Code now checks that style.
- Validation: plugin UI trees are checked for an invalid
BoxborderStyle. A bad style is removed and a diagnostic message is shown, and the box is drawn with no border. - Known styles only: the border renderer now accepts only known style names, and a style must supply all eight corner and edge pieces. Before, any style that was set counted as a one-cell border, and an unknown name fell back to a default.
- Validator order: some props now skip the standard per-prop check, while the
borderStyleaccounting still applies. - Syntax highlighting: when highlighting code in a diff (a view of what changed in a file) throws an error, the language is cleared so it does not keep retrying.
Why
A mistyped border style or a highlighting error should no longer break how things are drawn. Plugin authors get a clear message instead of a broken border.