Today i get the new version winHTTrack 3.43-5 from here site.Thanks HTTrack.
When i start downloading a web("google chrome source")
found it can only work as 1 connection, no matter how i change  the options
value and restart downloading.
i dont believe this, so later i create several new projects and try again, but
find this bug is true: 1 connection only.
(i'm not a new user of HTT but skilled using 3.40-2+swf version and also i'm a
js developer)
In following, i try old version again winHTTrack open the same  project:
working multi connections is ok.
So, bug in 3.43-5 ?