Querybuilder Results Filtering

I run into the following issue:
When in the results tab in QB, I can filter on some column. The dropdownlist shows all occurences. I choose an occurrence. When filtering on another column, the options are limited to the onces related to the first filter, AS EXPECTED. I choose an option.
Now, when I click the filter button again (for the second filter column) I get ALL OPTIONS in the resultset and the first (still active) filter is ignored. This is very annoying.
Has anybody experienced this too?