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The Timeline zoomratio has quite a lot of presets to which you set the zoom:
fit to:
-view all
-clip
-layer
-frames
-exposures
-selection
-keys
-Sound

i want to propose a useful one that i found missing:
Fit to Mark in/out

i also would like to see some sort of lock, as now, when you drag the timeline cursor to the edge of the view you loose the timeline zoom selection.
when you have a long timeline this happens at really high speed as well, and leaves you disorientated.
you can imagine that this can be quite frustrating at times especially when working on a specific spot in a long project.
i see the lock a simply a way of prefenting the cursor to push the selected view out of screen.

I like the new zoom idea a lot!
I'll add it to the list.

For the "lock", I'll also add it, but might take longer to do.