Was the January Bylaw valid?

Air Products and Chemicals, Inc. (Air Products) launched a tender offer to acquire 100percent of the shares of Airgas, Inc. (Airgas). The Airgas board of directors rejected these bids because they were lower than the market price. Airgas’s charter provided for a staggered board of nine directors—at each annual meeting, three would run for election.
At Airgas’s annual meeting in September, shareholders elected three of Air Products’s nominees to the board. Air Products also proposed a bylaw (the January Bylaw) that switched Airgas’s annual meeting to January rather than September. This change would mean that the next annual meeting would be in only four months. Air Products’s plan was to vote out three more directors in January, which would have the effect of reducing their terms by eight months. Shareholders approved this amendment with a 51 percent vote in favor. Because not all shareholders voted, the favorable vote actually constituted only 45.8 percent of the outstanding shares. To amend the Airgas charter and eliminate the staggered board would have taken a 67 percent vote of the shareholders who cast ballots.
Airgas filed suit, alleging that the January Bylaw was invalid because it was a back-door method of eliminating the staggered board without a 67 percent vote of the shareholders. (A bylaw is invalid if it conflicts with the charter.) The lower court upheld the January Bylaw, and Airgas appealed.