v6.2.0-beta.4

Features

• UI: Enable search for stories and fix / event listener (#14062)
• UI: Add collapse roots to sidebar navigation (#13685)

Bug Fixes

• Core: Support null and undefined in URL args (#14049)
• IE11: Transpile prettier down to ES5 (#14047)
• UI: Fix shortcut button focus border to support high contrast (#13699)

Maintenance

• Fix flaky color rendering (#14054)