show error on empty query. Fixes #505
show error on empty query. Fixes #505

unipept/unipept,unipept/unipept,bmesuere/uni-test,bmesuere/uni-test,bmesuere/uni-test,bmesuere/uni-test,unipept/unipept,bmesuere/uni-test,unipept/unipept,unipept/unipept