I just switched to 20.04 from 17.10, but the panel doesn’t work as well.
In 17.10, I had the panel at the top of the desktop, over on the left, and very small with the Task Manager on the right end of the panel. As I opened more programs and more windows, these would get added into Task Manager, and the panel would dynamically widen. If there was nothing open, the panel would be very short in the upper left corner of the desktop, but if many windows were open, the panel would extend all the way across the top of the desktop. (I don’t remember how I set this up to work, but it worked very well.)
This same panel functionality doesn’t seem to be available in 20.04. Now, if my panel is set to be very short in the upper left of the desktop, the Task Manager will not expand with more open windows. Instead, the items in the Task Manager just get smaller and get crushed together. (I assume it has something to do with the change from LXDE to LXQt.)
Anyway, making the panel be able to work as in 17.10, as I described above would be a great addition to 20.x