I tryed many different software to compare the chroma key. I mean the "basic" one just after pick the green from the clip. Saving a lot of time to adjust

Adobe Premiere Cs6: PERFECT! - adjust none
Shotcut V19.02.28: VERY GOOD (strange that the upgrade 20 is worst!!! - I downgrade!!!) (NOT ADJUST!!!)

Filmora 9: GOOD - after some adjust
Olive: QUITE GOOD - after some adjust

Davinci Resolve 16: GOOD - a lot of adjust

Kdenlive 19 and 20 and Shotcut V.20.04: NOT ACCETTABLE! (after hours of triyng!!!! )

Just go back to the shotcut 19.02.28 version is so unbelievable better!

Tell me what are your experience???

Use "Chroma Key: Advanced" -> Take the pencil (right of Color to Select). Draw up a rectangular on the project monitor.

mmmm... the same as I did.
No good.
I'v some graphic animation of a type appearing (is an animation done with slides with the grren background).
The squared green line of graphic element appear.
Especially if i use dissolving effect of a square (in slide presentation), in that moment of appearing the alpha is fully green....
I know premiere doesn't.