HP Touchpad issues in Umbrello

(Platform: Linux Ubuntu 18.04 (bionic) running Umbrello, version 2.30.3)

I am having serious usability issues in Umbrello on my HP Omen laptop 
which has a Synaptics touchpad working properly in all other 
applications:

1) When I try to do any graphical editing in Umbrello, the zoom feature 
immediately overreacts, and it is almost impossible to control it. Is 
this a known issue?

2) If I draw an association line from an actor to a use case, I cannot 
drag the anchors anymore after it has been created. If I click on the 
anchor point nearest to the actor, the actor gets selected; and clicking 
on the other point selects the use case. I also cannot drag the line as 
a whole.

3) There seems to be no (easy) way to make several use case elements the 
same size. I can work around it by selecting "Snap to Grid" and "Snap 
Component Size to Grid" and then resizing each use case manually. 
However, when I deselect these, the sizes change back again to fit 
whatever text there is inside of the object.

4) Is there really no way to insert line breaks into the text of a use 
case?

Thanks for any help!