The Display/Don't Display Junk option setting controls the displaying. The problem is that the trash can is always displayed.
In previous betas the junk option handling was in the Searching option, but I think the current place in Filters is much better, and for me suggests that the filtering happens not in the search time but at displaying. It would be nice to place the Display/Don't Display Junk option to the search result too and one could change it on/off even after the end of search.
Slow reply exp, sorry.

Agreed

LW 4.10.4 Spam filler works !
 

As I see, there is a plus redisplay phase when the result has turned to be junk, so the Don't Display and Dispaly at the Bottom settings now work good here with the mp3 spam.

one problem with spam
 

It's happen sometimes, that in one line the spam occurs 1, 2 or 3 times only, and the junk percentage is 0, 50 or 66% accordingly, so this line quality will contain stars and not trash can and that's why this line is not filtered out. In nornal case when the junk percent is 100%, this line filtered out when LW 4.10.4 redisplays.
It's no use to mark this as junk.
My main problem is why this line is not marked promptly as junk (and filtered out), when in this search there is already some line marked as junk with the same result name and size.
Sometimes the name is sadly a variaton, for example asd_qwe instead of asd qwe.

LW 4.10.8 junk problem
 

Sometimes one/two instances remain as not junk, two instances with 50 % junk value. I think that already the 1st instance should be junk, because this result (sha1) occurred already as junk.
Another problem that the number of instances (3/51) changed to (2/3) after marking as junk, and not to (2/51).
The new junk marking doesn't help.

Junk Filter
 

Some people have been thinking the junk filter filters out material that shouldn't be filtered. Well, the junk filter won't filter out what you haven't trained it to do. In fact, if you've never used the Junk filter, then nothing will be filtered out at all. I have just confirmed this (with settings on Strict/maximum.) If there's something wrong with your junk filtering, then tell the filter that the particular file is not junk, keep doing that & it will stop filtering it out. ie: select the file & press the not junk button. Else, tell the filter to forget all training. This can be set in the Junk Filter options under Tools>Options>Filters>Junk.

I thought I should add this to the archive since some people have been getting confused. Thus be careful how you use the Junk filter.