Some cases when the modification date of a directory is updated are listed here:
https://stackoverflow.com/a/46428666
Steps to reproduce
1) Open some non-empty folder on an NTFS disk that is monitored by Everything.
2) Check that folder's modification date and time, both with Explorer and with Everything.
3) Delete any file in that folder (in Recycle Bin or permanently).
4) Notice that Explorer shows updated timestamp for that folder.
5) Try to seek for it in Everything: for example, set Filter to "Folder" and sort by modification date (as we know that this folder ought to be the newest).
6) You will see that folder modification date in Everything index is not updated.
7) Go to Options>Indexes and do "Force Rebuild".
8) Now Everything will properly show this folder as the most recent element (probably except for the Recycler Bin itself) with modification date matching the time of file deletion.
Illustration
I have a folder "B:\Test" with file "file_1.txt" and subdirectory "Folder", that contains "file_2.txt". The local disk is monitored both by Everything 1.4.1.1009 x64 and Everything 1.5.0.1289a x64:
![Image](https://klimaleksus2.ucoz.ru/Here/21/everything_md_bug_1.png)
I deleted "file_2.txt" with Explorer to Recycle Bin behind the scene:
Notice that the bin itself is updated to 12:42, but the Folder is still at 12:39.
![Image](https://klimaleksus2.ucoz.ru/Here/21/everything_md_bug_2.png)
Then I reverted the deletion by Ctrl+Z / Undo in Explorer:
Now the Folder gets updated to 12:43, which means that an addition of a file is detected correctly. (In the bottom window, the modification date is listed in the one from the last column)
![Image](https://klimaleksus2.ucoz.ru/Here/21/everything_md_bug_3.png)
Finally, I tried to rename "file_2.txt" to "file_2_renamed.txt":
Here, the 1.5-alpha version detected the change and shows 12:45, while the 1.4-stable version still shows 12:43.
![Image](https://klimaleksus2.ucoz.ru/Here/21/everything_md_bug_4.png)
Background
I wanted to use Everything API (either as SDK or by calling es.exe) to reliably detect the fact that nothing was changed under the particular path. Then in case of a most recent modification date mismatch (on a file or a folder) my program will do a more advanced checks to find out, are there any real changes happened.
But now I faced the fact that a sole deletion of a file gets undetected and passes my test of checking modification timestamps, despite the actual parent timestamp was updated to the time of a child file deletion moment.
Versions of Everything tested
"1.4.1.1009 (x64)" – detects only file additions, but not renames and deletions;
"1.5.0.1289a (x64)" – detects additions and renames, but still not deletions.
Looks like subfolder (not sub-file) deletions and renames are detected correctly by both versions.