The Media Library and the recently released Inserter Media tab aren't in sync. This means that if a user uploads a file through the Media Library, it won't appear in the sidebar immediately. And even worse, if the user removes the file from the Media Library, the file will still show up in the sidebar (in this case, the user will be able to add the image to the canvas, and it will be rendered in the preview until the post is saved).

Step-by-step reproduction instructions

1. Create a post and add a file using the Media Library
2. Open the Media tab in the Inserter

The file doesn't appear in the sidebar.

1. Remove a file from the Media Library
2. Open the Media tab in the Inserter

The file still shows up in the sidebar.