We are experiencing significant performance issues in Dynamics 365 Customer Service Workspace when handling email activities, especially with email activities with inline attachments (such as images in signatures).

The problem is primarily caused by emails with inline attachments (such as images from signatures), which result in long load times and very often block the main thread — causing the frontend to freeze for up to 20 seconds. This behavior is more noticeable when emails contain a large number of inline images, as each one triggers repeated blocking calls during email load.

Since this behavior stems from a current platform design limitation, this idea is submitted to highlight the need for a solution — as the blocking calls significantly impact overall system performance.