Actual behavior:
In the DevTools console, right clicking a message from source "file.js" opens a context menu with an option to filter "Hide messages from file.js".  After filtering, the user has no indication that any filter has applied, aside from seeing a "N items hidden" label.

Expected behavior:
Message source filters created via context menu should be transparent.

Ways to address
- Modify the "N items label" to easily allow users to reset all filters. 
 Perhaps by adding a close 'X' button
- The "Hide messages from ..." option should add a field in the filter bar instead of adding an 'invisible' filter.