CTRL+w doesn't work when tabbar has focus

Affected version

• Nightly flatpak: Yes
• Other: 43

Steps to reproduce

1. Click on a tab in the tab bar (confirm focus ring)
2. Click ctrl+w key

Current behavior

Nothing

Expected behavior

Tab closes

Additional information

The shortcut is scoped to the sourceview. At a minimum it seems like it should include the tabbar, possibly, globally scopped.