Tab bar contains:
- Tabs for the subapps of the currently open app.
- Subapps tabs have an active state and an inactive state.
- First tab is always the browser subapp. It cannot be closed – doesn't have a Close button.
- Other tabs are typically closable (default behavior) but can also be configured as closable=false.
- Tab bar has close button to close the app itself.
- View buttons (tree, list, thumbnail) are part of the contained app, not part of the Tab bar.
UI specification https://app.zeplin.io/project/5acc848ede054e0a4865f805/dashboard