trackpad issues in Ubuntu 18.04? (NOT new click behavior)
I upgraded my Macbook Pro II from Ubuntu 17.10 to 18.04 (not reload from scratch). This is a native install of Ubuntu (dual boot with MacOS). Ubuntu 17.10 had no issues at all. For 18.04 things seem mostly fine except for one fairly infuriating problem: my trackpad now "freezes" while I'm dragging it.
If I move the cursor around (dragging with one finger) at some point (sometimes almost immediately, sometimes after a few seconds) it will freeze in place and won't move anymore, until I pick up my finger and put it back down again. That's annoying enough, but when I'm trying to drag-select text this just unworkable: it often fails to get through the entire drag-selection without freezing and I have to start over.
Note I have always been using the Mac-style trackpad and this is not (as far as I can tell) related to the new change regarding mouse click areas. This happens when I'm not clicking, just moving the cursor.
It also _feels_ like sometimes keyboard holds are freezing as well; for example if I'm holding down CTRL-ALT and using arrow keys to move between desktops I think sometimes I lose keyboard inputs. This I'm not sure about though, it doesn't happen often enough. It could just be I chorded the keys wrong or something. The trackpad issue is absolutely real and easily reproducible.
I've kind of lost track of what packages are involved here and I've searched for similar issues but found nothing. Also I see nothing of interest in journalctl output etc. If anyone has ideas or pointers I'm interested.