Collection Criteria "missleading"

[iham]

when adding a criteria to a collection, lets say title + "test" as the search text, i find objects with "test" in the title.

so far so good.

when adding a second title-criteria with "other" as the search text, i find objects with "other" in the title, but NOT with "test".

so i have tot title criteria but only the last seems to do the trick.

1. why does that happen?
2. why is a title criteria still selectable when already in use?
3. is there any documentation for the search text, that show how to use that correctly? (i found out about "OR" and "*" as keywords, i can use in the search text field)

is that a bug or a feature? (from UX-point, it's imho a bug.)