Balsamiq Studios, makers of plugins for Web Office applications. Mockups. Creating UI Mockups of Firefox Welcome to Open Source UI Design Want to join Mozilla's User Experience team as a open source contributer? Here are all the tools we use to create user interface mockups of Firefox: OmniGraffle Most of our mockups are created using OmniGraffle, a diagramming application for OS X. If you don't have OmniGraffle, or are on a different platform, you can still download the stencil images and use any image editor to create your mockup. Stencils These stencils are regularly improved, so check back to see if a new version is available (last updated 8/21/07). (To add the stencils to the Stencils panel in OmniGraffle, move them into the ~/Library/Application Support/OmniGraffle/Stencils folder.) Where to Contribute your Design Work After you've created your UI mockup, there are a variety of places you might want to post it: Questions.