App fails to load in a Firefox private browsing window

[richvdh]

Steps to reproduce

1. Open a firefox private browsing window
2. Go to https://staging.element.io

Outcome

What did you expect?

a working app

What happened instead?

Infinnispinner

Operating system

No response

Browser information

Firefox

URL for webapp

https://staging.element.io

Application version

No response

Homeserver

No response

Will you send logs?

No

[richvdh]

From the console logs:

16:15:57.588 unable to delete IndexedDBCryptoStore: InvalidStateError: A mutation operation was attempted on a database that did not allow mutations. [rageshake.ts:64:12](webpack:///node_modules/matrix-react-sdk/src/rageshake/rageshake.ts)
16:15:57.588 Failed to remove IndexedDB instance matrix-js-sdk::matrix-sdk-crypto: [object Event] [rageshake.ts:64:12](webpack:///node_modules/matrix-react-sdk/src/rageshake/rageshake.ts)
16:15:57.588 Uncaught (in promise) Error: Error clearing storage: [object Event]

[richvdh]

Introduced by matrix-org/matrix-js-sdk#2969

Does not look like this is 100% fixed, filed an issue in vector-im/element-web#24234.