It is a big improvement! With a mouse, it is perfect for me.
But... I now notice a difference between mouse and touchpad behaviour on your point 1 (maybe a touchpad config issue - I looked and couldn't find one though). Two finger scroll on the touchpad starting over a field still scrolls the field and not the panel.
I can't reproduce what you're describing (with neither touchpad nor mouse). Here are the conditions in which scroll wheel / two-finger scrolling is enabled:
If you're aware of those conditions, can you describe in detail how you trigger the two-finger scrolling on the fields?
The following is using the touchpad, where two fingers is equivalent to the mouse scroll wheel, and single finger is just like moving the mouse:
with the pointer over any part of the panel background, two fingers scrolls the panel
with the pointer over a field (either with the focus, i.e. clicked and highlighted, or without the focus, i.e. not clicked and not highlighted) two fingers scrolls that field and not the panel
once a field dropdown button is pressed and the list entries appear, two finger scrolling over any part of the dropdown does nothing; moving the pointer away with the list still showing then starting a two finger scroll causes the dropped down list entries to remain in the same screen location while the rest of the panel scrolls, so the dropdown list separates from the text entry line of the field (definitely not right).
Thanks for your additional tests which kept me perplexed and busy for quite some time. It's really hard to imagine the touchpad doing exactly the opposite of the mouse. Unfortunately, I haven't found anything in my code which might be related to the observations in your second point.
Can you maybe share details on the model of your laptop and the touchpad settings?
I've also did some tests regarding the third point (list detaching from the combo) and was able to reproduce this. It actually also behaves like that in the official version, but there it stops when reaching the next combo which makes the gap to be quite small. I'll fix that and prevent further scrolling of the Tag Panel if one of the fields is dropped down. Thanks for pointing!