Hierarchical view even it is switched off

[Rene Toepfer]

Why will be shown all images if I select the root of the DB even hierarchical view is switch off? The same applies if I select the first level of the structure, in my example "HALDE 4".
Please see what I mean at the attached screen grabs.

[David_H]

Why will be shown all images if I select the root of the DB even hierarchical view is switch off?

Because the option only works for folders - https://www.photools.com/help/imatch/#fw_basics.htm

If you select a folder, IMatch displays all files in that folder in the file window.
If the hierarchical display is on, IMatch also displays all files in sub-folders of the selected folder, grouped by folder, up to the number of levels chosen in the hierarchy menu.

And

If you select a media or drive node, IMatch displays all folders on that drive/media, independent from the state of the Hierarchy button.

[Mario]

The File Window layout is irrelevant. The hierarchy drop-down controls how many levels you see, if files are grouped by folder etc.
If you select an entire disk, IMatch can display all files in a heap, show only one or two levels, group the files by folders. All this is controlled by the The Hierarchical Display Mode (Displaying files in sub-folders, child categories etc.)

It works slightly different between folders, media/disks or the entire database. But it is very intuitive you you'll figure it out. Just turn on the options and see what results you get when you look at all files on an entire disk.

If you select the Database node to bring all files in your database into the scope, you'll notice that some options in the hierarchy drop-down are disabled. You can either group the files by folder (slower) or just treat them as one heap of files. For the typical use-cases where you would work with all files in the database, the no hierarchy mode is usually sufficient and lots faster than grouping files into deeply nested folder hierarchies.
Depends on the number of folders/files in the database of course. What makes no difference for 50K files may make a lot of difference for 500K files.