I haven't seen either of those issues, and don't remember anyone else here mentioning them. Can you post some screenshots of the issue? And maybe your computer specs, especially your graphics card?
I have no issue with performance .
Ive had an issue with this on many pcs as well as different versions of Solidworks
The picture is a result of me placing a balloon and linking it to a leader without a border
This is the process that I have to use from time to time unfortunately, otherwise they work fine