I just fixed a couple of bugs in DataMgr which caused an update in both DataMgr and in the com.sebtools pack. The com.sebtools package also includes an update to FileMgr among other components.
One bug fixed dealt with filtering by NULLs the other was with handling what I would call "voids" in a structure. That is, where a key value is essentially obliterated, but the key will still be found when looping over a structure. This happens when a key of a structure is set to the result of a function that doesn't return anything.
So, if you are using either, you might want to upgrade.