I'm sorry, but the knowledge sources do not mention an open or :open prop for the UHeader component in Nuxt UI Pro. According to the official documentation, the UHeader component does not support controlling its open state programmatically via an open prop or v-model:open. The available props and slots are for customizing the title, menu, mode, and toggle button, but there is no documented way to control the menu's open state directly through a prop like open or v-model:open UHeader Usage UHeader Mode.
This is different from components like USlideover, UModal, or UDrawer, which explicitly support open state control via v-model:open or an open prop Slideover Control Open State Drawer Control Open State Modal Control Open State.
If you need to programmatically control the open state of a menu, you may need to use a different component (such as USlideover, UModal, or UDrawer) or implement a custom solution. If you believe this should work, please double-check the documentation for any recent updates or consider opening an issue on the Nuxt UI Pro GitHub repository.
Summary:
The UHeader component does not support an open or v-model:open prop for programmatic control of its menu state, based on the current documentation. This is likely why your approach is not working.
Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: