To create a fixed element, select a Layer or Hotspot and check the Fix position when scrolling option in the PROTOTYPE tab of the Inspector. Alternatively, choose Prototype > Fix Layer Position when Scrolling in the menu. This is handy when you want to fix a row of tabs at the bottom of an app design or have a floating button on a website, for example.
Sketch has two methods of calculating where a fixed Layer is displayed when a Prototype is played:
- Proximity - if you place Fixed Layers at the top or bottom of an Artboard, Sketch assumes that you want to pin them to the top and bottom of the Prototype window respectively. Any Layers you fix elsewhere will display relative to their overall position in the Prototype.
- Pinning - When you set a Layer as Fixed, you can use the Pin to Edge options in the RESIZING section of the Design tab to specify the exact edge that you want the Layer to be pinned to. This is useful if you want to design in a WYSIWYG fashion so that where you draw a Layer can be reflected directly in a Prototype.
Any Pinning options you set will override the default Proximity setting.