Hi @BurningTreeC congratulations, a very impressive piece of work. It is very elegant and usable, and works very smoothly. Given the universal appeal of the sidebar resizer I think it is a very strong candidate for inclusion in the core, if you’d be interested.
One thing that caught my eye was this line:
tiddler="$:/metrics/storyright $:/metrics/storywidth $:/metrics/tiddlerwidth"
It feels a bit uncomfortable using an attribute named “tiddler” for a list of tiddlers.
Beyond that, I’m sure it will already be part of your plans, but more interactive examples would be very valuable.