Firefox 15 nightly received two new exciting developer tools, Responsive Mode and Layout View

It a fact that Mozilla is seriously focused on Firefox, adopting a fast release cycle and delivering fresh new features in every "corner" of the notorious web-browser, used by millions and millions all over the world.

Announcing a new default theme, Australis, that is to probably land in the near future (according to various "official rumors" it is to land not in Firefox 13 stable, but shortly after), hasn't concentrated Mozilla's energy only on shiny polish, by contrary, it only completes a global approach where UI development goes hand in hand with the under-the-hood improvements.

Firefox 15 nightly build has just gained two new exciting tools, designed mainly for developers:

• Responsive Mode is a fancy animated web-view that allows one to test/observe/analyze a web-page in various predefined sizes (320x480, 360x480, 1920x900, etc) and custom sizes by clicking&holding&dragging the page just as regular windows, furthermore the web-page can be easily rotate via the rotate button.
  Open the Responsive Mode via Firefox-->Tools-->Web Developer-->Responsive Mode

  

• Layout View introduces a fancy way of visualizing the size of various elements from a web-page by correlating the highlighted selected item with a blue-ish rectangle where descriptions are displayed.
  The Layout View can be accessed under Firefox-->Tools-->Web Developer-->Inspect