A slider window assembly for an automotive vehicle comprises a fixed glass panel adapted to be installed in a window frame defined by a body panel. The fixed glass panel is bonded to the window frame by an adhesive bead and defines an opening. A sliding window opens and closes the opening and includes an edge that is received in a guide rail that is adhesively bonded to the fixed glass panel. The guide rail defines a channel for the edge of the sliding window and also includes an extension that is bonded to the window frame by the adhesive bead. In this manner, the guide rail continues to support the sliding window in the event that the fixed glass panel is unable to provide the primary support function.