I have created an issue for the performance issue.
there maybe alternative ways but these are the ones that come to my mind
I have reproduced the issue and will be fixed in v4.4 preview rc2
we have addressed some issues on rc-1. rc-2 will be released next week. you can wait for rc-2 for more stable version or let us know your findings at rc-1.
Can you check if your Login Page is MVC or Angular. Because it's changed in 4.3x
paging in FileManagement module will be implemented in v4.4
last question is Identity Server Seperated ?
also which version did you update it?
It looks like the one after update looks better :) do you want to keep it as in the first image (aligned left)