German has two demonstrative series, the der (die, das) series and the dieser (diese, dieses) series. Both have been claimed to be topic shifters, taking up a non-topical antecedent and promoting it to topichood. However, der can form topical referential chains, while dieser cannot. We operationalize discourse topichood via questions and provide evidence from a corpus study and an acceptability study that while dieser is indeed sensitive to topichood and avoids topical antecedents, der is compatible with topical antecedents. We hypothesize that only dieser is a discourse topic shifter, while der marks a sentence topic.