Now, MozillaWiki released the screenshots of how Firefox 4.0 would look like. Mozilla wiki says these are released for the feedback for 4.0 windows theme Mockups and any time that gives us chance to imagine how the Firefox 4.0 user interface and features going to be.

A month ago the company released Firefox 3.5 and after three weeks Mozilla released screenshots of Firefox 3.7.in which it adds a change to the Tools bar and Embracing Glass design. And recently it has released screenshots for Firefox 4.0.  Let’s look at themes that reveal something about Firefox 4.0. 

These pictures, all of Firefox in Windows OS discloses that the company is struggling to choose between two primary designs: tabs-on-bottom and tabs-on-top.

The Tabs on bottom is the current norm in Firefox. And the the tabs-on-top looks almost exactly like the Google Chrome browser.

 Version A Tabs on bottom

1. There is no file menu
2. It’s much like Google Chrome interface
3. There is also tools button beside bookmarks much like the wrench button in Google Chrome.
4. Bookmarks appear after address bar.
5. Reload button comes in the address bar.

It’s complete change in UI for Firefox when we compare to present Firefox 3.5 or older versions.

Version B tabs on Top

Positives

• Save Vertical Space
• Shorter Mouse Distance to Page Controls
• Efficiency/Remove Visual Complexity - Right now the tabs have to be connected to something. So we are adding an extra visual element for them to connect to.

Negatives

• Breaks Consistency/Familiarity - Moving things confuses existing users.
• Title is MIA - With the space removed from the title bar you only get the truncated version in the tab.
• Longer Mouse Distance to Tabs - Takes longer to mouse to a tab.
• Lost Space - Sandwiched in between the application icon and the window widgets you lose some space.

Combo Stop/Refresh /Go button

In the above Screenshot

• Firefox don’t require 3 buttons for refresh, Stop and Go in the navigation bar, all in one combo button will do the go, stop and refreshing the web pages.
• They are all included into one button on the right hand side of the address bar, Instead of separate buttons for each of these functions.

Attached at the end of the location bar.

• Turns green when you start typing.
• Turns blue on hover.
• Blends with the location bar when at rest.
• Turns red when a page is loading.
• The proposed iconography is mostly colorless. Adding color to these temporary action driven buttons will make it more obvious something is going on.