Motivation

The view of the messages on the subscribed topics is not readable

Detailed design

I'd like to have a tree view of the topics. The roots are the subscribed topics, the sub nodes are the direct sub topics, and so on.
The displayed messages are filtered by the selected node in the tree so I can see only the messages from the branch I'm interested in

Alternatives

I don't see any

More detail (optional)

A plus would be a configurable summary of each nodes after the name of the sub topic (total messages since connection, count of subtopics, ...)
Also making possible for the tree path to be higlight when a message comes would be great to identify the active branches of the server
In that case it would be also nice to click on a node to set the topic in the "send message" area