Feature Request: Improve the UX for manually added person properties

Feature request

Is your feature request related to a problem?

When adding person properties manually (e.g., via the UI), there’s a significant delay before they appear in the interface and become available in autocomplete fields (e.g. for feature flag targeting). This delay causes confusion and makes it harder to work efficiently with feature flags for individual users.

In particular, this affects users in privacy-sensitive industries (like German edtech), where PII such as emails isn’t tracked by default. Teams often manually add an email to a user’s profile just before targeting them in a flag, and the delay breaks that workflow.

Describe the solution you'd like

Improve the experience of manually adding person properties by:

• Reducing the delay before changes appear in the UI (especially in the person page and autocomplete fields for feature flags).
• Optionally: showing a visual indicator or toast confirming that a property was successfully queued/saved, even if it hasn’t propagated yet.
• Optionally: adding a “refresh” or “reindex” button on the person detail page to speed up the process manually if needed.

Describe alternatives you've considered

• Using distinct_id in feature flag filters instead of person properties — this works but isn’t human-readable.
• Using the SDK to send the property — not always viable for one-off or post-hoc changes.
• Writing a SQL query to confirm the property was added — helpful, but not intuitive for most users and doesn’t help with flag targeting UI.

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/31920 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/34220)

Debug info

Kind: bug

Target area: data_management

Report event: http://go/ticketByUUID/f8f31c41-2769-460f-9403-64c58b2265db

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/01973aae-a163-75a0-9e7d-45b67487128f?t=302

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%2201973aae-a163-75a0-9e7d-45b67487128f%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://eu.posthog.com/project/8482/persons/eaa4ac39-3f14-5302-851e-3cfbfe33f5d5

Persons-on-events mode for project: person_id_override_properties_on_events

Start at the person detail page and the feature flag targeting autocomplete in the data_management area, then reproduce the delay after manually adding a person property. Trace when the property becomes visible and selectable; done should be a materially faster update or a clear queued/saved status, with any refresh or reindex behavior defined.