Double-clicking a host (or clicking an already selected one) opens a terminal tab in the center dock. Three headless tests drive the real panel with real pointer events. They use gpui-base's test_support because gpui-kit's test-support feature drags in the gpui-fast dependency tree, which conflicts with gpui-pre 0.3.9 on Windows. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>