After a year's delay, construction crews Monday were installing the final glass panels in on the upper floors of the new Little Caesars headquarters on Woodward Avenue near the Fox Theatre.

Originally expected to be opened last summer, the building was delayed over an apparent problem with the unique pizza-slice wedges of glass that form the facade.

The Ilitch family's Olympia Development has never commented on where the problem lay. There has been speculation that the tower's heating and air conditioning system was causing a vibration that damaged the glass panels.

More:Those pizza-slice windows may be delaying Little Caesars HQ opening

More:Pizza-slice-shaped windows unveiled for new Little Caesars HQ

Little Caesars has said recently that its employees would be occupying the new headquarters tower shortly.