Same on the M?

No - if I understand what you are asking about. P162 of the Montage ref doc shows a 'Part1 - Category Search' and there is no 'Attribute' selection to the right of the 'Bank' dropdown.

That is as described on page 161:

Attribute (Performance Attribute)
Filters the Performance List by Attribute (page 145). This is not available for Part Category Search.
Settings: All, AWM2, FM, FM-X+AWM2, MC, SSS, Single, Multi

Contrast that with the graphic on page 447 of the M operations doc which shows the 'Attribute' button at the top left.

So the M does allow you to set filtering for part and performance merge category searches.

But the actual filtering on both classic and M still have the same limitation (IMO) - The 'engine' attributes of AWM2, FM-X and AN-X (M only) operate only in an AND relationship. 

You can't search for performances that have at least one part that is FM-X (or other type). Using just the 'FM-X' attribute the search results will be performances that ONLY use the FM-X engine. A performance that uses both FM-X and another engine won't be listed.

And if you use both 'AMW2' and 'FM-X' the results will only be performances that use BOTH engines.

The classic doc, p.145 shows a 'Tg Flag' parm that allows the user to set the engine type. I don't see that on the M.  

That same graphic shows a 'Motion Control Flag' that can be used in the search filter even if the performance doesn't use motion sequences. The M has an equivalent 'MC Flag' as shown on p.205 of the ops doc.

I don't see it on p.162 for the classic but on p.447 for the M you can see a 'Source' dropdown that lets you select Part 1-16. Unfortunately the performance list isn't actually filtered on number of parts. So you can set that parameter to part 7 but select a performance with only 2 parts .

LITTLE KNOWN FACT: All performances actually have 16 parts. And part 1 is ALWAYS active. But the other parts exist whether they are active or no. So even though part 7 isn't ACTIVE or part of that performance you will still get a new part that copies whatever is in that part 7 buffer to your performance.

If you are lucky that will just be a harmless 'Init' part. If you are unlucky it could be left over garbage from when a sound designer created and used part 7 for something and saved it. Then later they deleted part 7 before delivering the preset to Yamaha. Deleting a part doesn't actually clear the storage area for that part - it really just sets the 'Part Switch' to OFF.

The 'Part Switch' indicates if a part is active in the performance - see p. 237 of the Data List doc. You can't set it directly in the UI but you can set it using SysEx.

So if I understand, in the M too, attribute for part category search don’t filter awm from fmx and anx. Why like this? This is an anomaly, am I right? It should be useful, specially when you need to manage the number available of polyphony voices in a performance, no? This is for ideascale but unfortunately not many montage customers go there and so in return, difficult to think that Yamaha pay attention too.

For sure part are a little special as you can have in memory (where?) many part with the same name but different sounds, it will need maybe a kind of part labeling, each time you create a part, you could have choice to label it or not, as per performance favorite and then it should be possible to have attribute for part too.

So if I understand, in the M too, attribute for part category search don’t filter awm from fmx and anx. Why like this? This is an anomaly, am I right? 

See p.20/21 of the ops doc

Select an attribute or combinations of attributes. Depending on the combination,
the filter uses the conditions AND or OR.

Filter:
Exact match · AWM2, FM-X, and AN-X
AND condition · MC, SSS, and Smart Morph
OR condition
· Single, and Multi
· MOTIF XF, MONTAGE, and MONTAGE M

On your own instrument it is easy to just test the different combinations and you will see that you can NOT get a list of performances that have at least one FM-X part by using only 'FM-X' part if those performances have at least one other part. Selecting both 'AWM2' and 'FM-X' will only return performances that have BOTH part types and selecting only 'FM-X' will list performances that ONLY have FM-X parts.

Since that is 'working as designed' it doesn't fit the definition of an anomaly.

Improving the 'part category search' would be a good IdeaScale suggestion.

For sure part are a little special as you can have in memory (where?) many part with the same name but different sounds, it will need maybe a kind of part labeling, each time you create a part, you could have choice to label it or not, as per performance favorite and then it should be possible to have attribute for part too.

Yes - category searches seem to be primarily 'performance' oriented rather than 'part' or 'attribute' oriented. It is likely that way because of a cost/benefit issue.

In order to do effective searching for multiple attributes they would have to provide a way for the user to combine attributes using a BOOLEAN expression that can accept typical components like: OR, AND, XOR, NOT and use parentheses for compound expressions: (A AND B) OR (C AND D)

The cost involved very likely exceeds the benefits created. 

I'm not sure if Ideascale was a thing or not, but I've mentioned the limitations of [CATEGORY SEARCH] (on Montage Classic) before.   The filter system is fairly rigid and doesn't allow for certain combinations.

https://yamahasynth.com/community/postid/24151/

... there's other threads out there too. 

I'm with you.  Wish there were certain combinations that could be searched for but can't.   With such a huge selection of sounds managing these becomes an important feature.  There's always room for improvement.

It can be frustrating when things don't work as you'd expect. 

You can go on being frustrated, or adapt. 

From time to time,  I would just sit down and go through Performances one-by-one listening to their Auditions.  If any particular Part stood out as something I might want to use,  I would delete all the other Parts, and Store it as a Single Part Performance.  Of course I would rename it as something appropriate to me (e.g. Crazy Diamond Sax v1). 

I usually had some "Song Project" in mind whenever I did this, so I already had specific Timbres mentally listed.

It can be the case where you have been through every Performance, for example "Woodwind: Saxophone" and found nothing to suit. 

Then, one day you are listening to an "unrelated" Performance (e.g. Pop Ballad) and sitting in Part 4 is the perfect Sax sound you've been looking for.  Don't hesitate, Store it, or a day later, you've lost it. 

Over time you'll build up an arsenal of your preferred tonalities.

On a final note.  At some point, it helps to break free from a reliance on presets. This means learning how to use the Montage/MODX as a Synthesiser, and thus learning "Sound Design". 

In the above examples, I would have been listening for a specific Timbre/Tonality, rather than context.   

Once I have that "Tone", then I can repurpose and shape it to my specific needs via editing.  

Don't get me wrong, I love Yamaha and my MODX, but I have learned that "hoping and waiting" just makes me stagnate.

Very few IdeaScale "improvements" make it through to production. Even then, its a long time waiting, and eventually may not be what you had in mind.