I have found it out - only it doesn't help because I don't understand it ;-)
When I untick the checkbox to "hide Null values" on the dimension, there are the 110 missing emps.
But what does that mean - my dimension is not the emp_no (PN), but a category - those 110 are not in any of those categories, but still there are no categories around the ones I have where I might be losing out on someone?!
I blublubludrdrdrdrwaawaa... it's way too warm for this kind of thinking.