Progress percentage... what mean?

[Bartoloni]

probably the screen resolution changed from 1080p to 4K... and the line probably has an hardcoded height in pixels?

[VCRvideocapturing]

Like I wrote, I didn't change anything aside from updating for a while, so any changes should be related to style changes and changing the style to 'windowsvista' likely will get you back to the old view.
see: https://imgsli.com/NDU0Mjg0/2/1

Cu Selur

I did what you said 
View change from default to vista but after doing that it caused ghosting in the menu all of its different options,  so I ended up changing it back to default.

Please try changing it to vista on your system and you will get the same ghosting (shadows) too when you change, but it did fix the rounded edges.

[Selur]

The broken alpha for combo boxes are a bug in Qt, which I worked around in the devs a while ago,...
=> use latest dev