Users clicking links are sometimes shocked when the container isn't what they expected. Using the status panel would give the user a warning about what container it would go into. If we end up putting assignment into native, we can use this to show the assignment instead. My other hunch was that if we can detect if the user hasn't redirected after clicking the link then we can use that to suppress the assignment warning.

For the assignment: Baku suggested we can use OnLinkClicked of docshell here to detect when user click a link. We can use that to establish in between clicking the link and moving to a container if the page redirected to a different hostname. For form submission and redirects the assignment error screen should still be visible to prevent the user being sent into their container unexpectedly.

Expected: - User hovers link: - Assigned container to hostname: status shows assigned container icon and name - User is in a container: status shows the current container icon and name - None of the above: status behaves as current with no container or icon - User clicks link: - If request redirects to a different assigned container in a different container: show warning page - Normal redirects even to different hostnames won't show assignment error Example: 1. User assigns paypal to "finance" and example.shop to "shopping" 2. User visits example.shop in "shopping" container 3. User hovers a paypal icon showing a finance icon status 4. User clicks icon which redirects to a finance container in a new tab 5. User finishes paying and submits the form 6. User is redirected back to example.shop 7. Browser opens a new tab confirming the redirection from paypal to "shopping" container.

Bulk change per https://bugzilla.mozilla.org/show_bug.cgi?id=1401020