Systems and methods for improved window mounting on electronic devices are provided. A window mounting assembly can include a heat activated adhesive, such as a heat activated film (“HAF”), which can be used to secure a window to an enclosure. In some embodiments, heated air can be blown in from a bottom side of the window, which can provide better offset control in the assembly. In some embodiments, an undercut can be made in the enclosure that can act as a trap for HAF overflow. An overhang that is created by the undercut can reduce the visibility of HAF overflow from a user. In addition, the heated air that is applied to the window can create a high pressure region in an area underneath the window. The high pressure region can direct the HAF overflow away from this area and towards the undercut in the enclosure.