While Myalls does not appear to have voted in both Illinois and Wisconsin in the same elections – instead alternating elections – the fact that she most recently voted in the 2012 presidential election here in Wisconsin puts her eligibility to serve in the Illinois State Legislature into question, given the clause in the Illinois state constitution that a person is eligible to serve as a member of the General Assembly if he or she is a U.S. citizen, is at least 21 and has lived in the district that he or she is to represent for two years preceding the election.
Given that election day in Illinois is November 4 this year and was November 6 in 2012, Myall would appear to be two days short of meeting the residency requirement in Illinois.
Via Illinois Republican state rep candidate alternated voting in WI & IL in recent years @ Blogging Blue.