Dear Sir/Madam,
Thank you for your answer. I already own an earlier version (4.40).
I was happy with that one, but was dealing with annoying bugs, i.e. the automatic gap closing which does NOT belong to professional editing...
Also some bugs of unexpected multiple selection of tracks, etc.
I decided to try the newest version, and was super-happy to see that these issues have been resolved! However, I noticed this annoying dark background with a hostile to my eyes green-blue wave.
There are also white vertical lines on the track, which I don't know what they are and what is their use -if any ( I 'll try to attach a screen-shot). https://ibb.co/m8QKVYy
I also did a recording test and there is a noticeable time-delay between sound and video, in 720p which did not exist in the earlier version. My computer is very fast (8-core, 16GB memory, SSD disk, etc) , so there is no issue there.
Maybe I do something wrong, but cannot figure out what..