When prototyping I use the auto stretch function in Invision. However, I'm having issues with my fixed footer (which is a chat button). In Sketch, I have it set up as no background behind the chat, directly under the footer, with a height of 48 pixels. When in build mode the dark footer extends below where it should and covers the background of the fixed footer making the preview mode very unappealing. (see both examples below) Does anyone know what is going on with this and how it may be fixed?