Unwanted Category Refresh

[Darius1968]

Okay, I'm clicked on the "Canon" category for the make of my camera.  I have my search bar with "EOS" entered to get only images of Canon's EOS series. 
I'm combing right at this point for images I might want to upload to a website.  So I created a category, "_For Consideration", to which I assign images I may be interested in.  My problem is that when I've determined an image that is to be uploaded and assign to this category, the highlighted image now becomes the very first one in the "Canon" category.  How can I prevent this? 

[Mario]

You mean when you assign an image via the Category Panel to "_For Consideration", the current file window reloads and brings the selected image to the top of the sort order? Which sort preset do you use in the file window (toolbar, left)?

[Darius1968]

I use a custom sort preset I created, "Pixels", which sorts starting with images having the most pixels first, and consecutive images have lesser and lesser pixel count.  I do assign the image via the Category Panel to "_For Consideration", and then the sorting order stays the same, but the problem is that the highlighted image switches to the very first image in the file window, but I don't want this. 

[Mario]

But you are still looking a the "Canon" category, right?

Why should the sort order change when you assign a file to a category?
Does your sort preset maybe use categories? Or do you show categories in your file window layout?

Do you mean that the file window just reloads and re-positions the file so that it is shown at the top of the file window, or does the sort order really change?
When the file window has to reload because of a change you make in IMatch, it may re-position the currently focused image (the file window scrolls one row up or down). This is OK. But that the file window changes the sort order would be wrong.

[Darius1968]

Okay, here's a scenario that might help illustrate the issue I'm having:
Right now, I have roughly 90,000 files in my database.  However, my filter (only the folder filter, restricting to x # of folders, subfolders, etc), now being active, gives me some 8,000 images to work with.  I scroll to where I'm about maybe 20% of the way down my thumbnails, and I now have an image I'd like to assign to a category.  I'm gonna do it now.  I did.  The image has effectively been assigned to the category I want, BUT ABRACADABRA!!!  The scroll bar has somehow mysteriously been set back to the top of the thumbnail list, which is what I don't want!  How can I prevent this 'refreshing'? 
Okay, to answer one of your questions, the sort order does not seem to change at all, just that the scroll bar position has shifted.  The relative position of the image I've just assigned to a category stays the same, but I'm far away from it, as I'm at the top of the list.  So, this refreshing doesn't just "scrolls one row up or down", it takes me all the way to the top!  This is happening regardless of which sort order preset I'm using.   

[Mario]

So the problem is that the file window repositions.

You have a large number of files filtered down with a filter.
You perform category assignments and this causes a lot of changes to the database, from categories to collections, histories etc.
The filter also needs to reload completely, because it cannot know if your recent changes to the database may have an impact on the filter result. The filter therefore loads all you 90,000 files again, applies the folder filter and sends the resulting set of files to the file window. The file window reloads.

It should automatically re-position to the last selected file and try to restore the original top-row so the current position within the file window stays the same.

What element (database node, media node, drive node, one or multiple folders) have you selected in the M & F View?
Do you use a hierarchical display mode? If so, which level settings?
Which sort preset do you use?

I just made some tests.
Select the database node, apply a filter (10,000 files down to 500).
Scroll down until about 1/2 of the files. Select some files and assign them to a category.
The file window not even flickers, selection and position do not change.
The same happens when I instead select a folder in hierarchy mode.

[BenAW]

The scroll bar has somehow mysteriously been set back to the top of the thumbnail list, which is what I don't want!  How can I prevent this 'refreshing'?

Are you perhaps using Hierarchical Display, perhaps even All Levels?
This could explain the behaviour you're seeing imo.

A faster way to work with your 8000 images would be to:
- find them using filters etc.etc.
- assign the result to eg. Bookmarks, Pins or similar.
- work with this set using the Collections view.

[Darius1968]

Ben & Mario,

No I'm not using hierarchical display, it is off! 

"It should automatically re-position to the last selected file and try to restore the original top-row so the current position within the file window stays the same."  This is absolutely the case, if I'm looking at a filtered view (8,000 files) of my entire database (90,000 files) via the "Media & Folders" tab, where I have "Database" selected at the top of my folder list.  However, the unwanted refreshing happens if I'm trying to assign categories via the "Categories" tab, where I've selected the category "@All" at the top.  Furthermore, if I'm in the "Categories" view with the scroll bar half way down the file window - and I subsequently switch to "Media & Folders" view - and then switch back to "Categories", the same exact scenario presents itself; The focus is set to the first thumbnail with the scroll bar at the very top again! 

So, all in all, I'm getting difficulty when I'm making use of the "Categories" view and not the "Media & Folders" view. 

BTW:
Interesting to now know that when in the "Media & Folders" view, it's possible to select more than on folder at a time!  How come, however, this only works for selecting sibling folders, and not selecting a folder and then a child folder? 

[Mario]

BTW:
Interesting to now know that when in the "Media & Folders" view, it's possible to select more than on folder at a time!  How come, however, this only works for selecting sibling folders, and not selecting a folder and then a child folder?

That's in IMatch 5 since build 80 or so. And as documented you can only select multiple sibling folders. See the corresponding help topic for details:

Click in the Media & Folders tree to make it active, then press <F1>. In the help topic scroll down to the section with the heading Selection to see the corresponding documentation.

Regarding your other problem:

Please file a bug report (just a short text and a link to this topic). I will then look into this.
My first impression is that you create a worst case scenario by combining a filter on the entire database with category updates while you work in the category view. Every change you make to a category causes the filter to invalidate and reload, which is no fun for 90,000 files. And this can easily cause IMatch to reste the focused file in the current file window back to the top - which is the effect you see.

I don't test all these fringe cases, and they are often so complex to handle that it's not worth the effort.
Just put your 9000 files into a (temporary) collection, or at them to a dot, pen, flag or bookmark collection. Then you can work on them without filtering down the entire database with every click you make. Much faster and I guess that the current image also sticks.