Tab title colours don't update when toggling light/dark mode if hidden

Reproduction:

1. Open a window
2. Hide Orion
3. Toggle between the system light & dark modes
4. Reactivate Orion and observe that the tab title colours have not updated

(I use vertical tabs so haven't tested it with the other tab layout options)

This only happens when the window is hidden – the tab title colours update correctly if the window is visible when toggling the system light/dark mode.

This screen recording shows the issue (Orion is being hidden via the ⌘H shortcut):

Version 0.99.132.0.3-beta (WebKit 621.1.2.111.4)

Sequoia (15)