It's been less than a month since 3.5 was released, and already Mozilla is talking about 4.0. More than talking, in fact. It's released some screenshots of mockup designs that it's considering for the next iteration of its browser.

One notable feature is a tabs-on-top design that mimics Google's Chrome browser. Startlingly similar, in fact. Mozilla can't decide whether it likes that approach or not, summing up the pros and cons like this:

- Save Vertical Space
- 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.
- Shorter Mouse Distance to Page Controls".

- Breaks Consistency/Familiarity – Moving things confuses existing users.
- Title is MIA – With the space removed from the titlebar 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".

An option to pick between the two might be nice, but probably presents a sizeable coding challenge. As the release of 4.0 approaches, we'll probably get a better idea about what the Firefox community wants. If you have a strong opinion, then go share it on the company's wiki.