Thank you very much, toby_toss, for your very kind help!
I tried again with 650 and with 680 (I checked in the "About" pane for not mixing them up).
I tried all possible combinations for checking/unchecking settings, building them up one by one, and removing them one by one from a "full set".
Those settings did not change anything, including the setting "Auto-add wildcards", whilst it's clear as day that for SOME of my observations, this option checked/unchecked SHOULD have made a difference:
will "find" ANY folder, i.e. NA hits (NA being for "non-appropriate"), but NO files ("no" meaning not any, nada)
will bring ANY folder (most of them NA), AND SOME relevant files, i.e. those BEGINNING with "0" only (i.e. even when "auto-* is ON", by which I expect that files (and folders) would be found that are named abc0def)
will bring ANY folder (most of them NA), AND ALL relevant files, i.e. those beginning with 0, and those which have a 0 withIN their name
So I installed the portable version, "Portable 2014", which is 650 again, and let the settings on default, which means, in Quicksearch/filter/starter settings:
first pane (2 settings): second one checked; second pane (5 settings): first 3 checked
Result for Portable 650:
In a folder with lots of files and just 2 folders (1 relevant, 1 not):
displayed the relevant folder one (while hiding the NA one: so far, so good!!!), and NO file (i.e. this filtering HID some 10 relevant ones!!!
displayed the relevant folder (an this one only: good!), and the files beginning with 0: very good, since it seems this is the desired result,
even though it should be said that the choice for filtering/displaying folders only (1.) or folders AND files (2.) should not be made dependant on an asterix, which would have quite some other meaning in every other program worldwide
(relevant folder: 0abc, hence to be found with 1. und 2. = ok, but relevant files: 0abc, 0def, 0ghi, etc., so they should have been found by 1., too: let's remember that "auto add wildcards" setting was ON (by default)!)
And then, if an asterisk toggles between folders-only and folders-and-files, what about the third alternative, "FILES ONLY"? These 3 alternatives should be set by a dedicated three-way option!
As seen under B, it SEEMED that the Portable version alone (!) worked correctly, albeit in a weird way (* needed in spite of the "auto-*" option).
So I tried, with the very same settings, and again with Portable (650), a similar search in a sibling folder, but which only contains 2 files, 0abc and abc0def, which I put in there for checking, but 400 folders, of which some only are relevant.
And boom, the Portable version failed here, as 650 and 680 had failed everywhere, and in the same sense:
shows all folders (most of them NA), but hides the two (RELEVANT) files (relevant at least if we supposed that the auto-* option set worked correctly which obviously it does not), and
shows ALL folders again, most of them NA, and also the two relevant files; by the way, I waited several minutes in either case, in order for according FC Portable the time to "compute" if that time was needed, but there was no difference in the result after several minutes, from the immediate (and totally incorrect) result: in both cases, 393 folders were displayed, about 385 of them wrongly, and in the second cases, the 2 relevant files were displayed, too.
Thus, I repeated these filterings 1. and 2. (same folder, same Portable) with your settings, i.e. not the defaults, but "anything set ON":
Results identical to 1. and 2., i.e. with 0, all folders (most of them wrongly), and with 0*, ditto plus the two files.
From this, I suppose there's some additional work for the developer, but from my experience prior to this (see my previous posts), I deduct that this work will NOT be done if I'm the only user to whom to rely, so if these various bugs here are to be exterminated, it should be advisable that my findings be backed by fellow users'.
Again, thank you so much, toby_toss, for your very kind help, and perhaps, if you can confirm my observations, the developer will become interested in this issue, too?