Home Dash is a new add-on from Mozilla Labs' Prospector project that re-imagines the Firefox interface for Firefox 4 on Windows, Mac OS X, and Linux. It removes nearly all defining features from the interface in an attempt to emphasize the contents of the Web page you're viewing. Gone are the status bar, bookmark bar, navigation buttons and URL bar, leaving behind only the dedicated Firefox 4 menu button from the upper left of the interface.
All those components get replaced with a translucent Firefox logo below the menu button. Click the logo or use the Control + T hot key and the new "dashboard" appears, flush against the right margin of your browser. The top row shows your open tabs, with pinned tabs on the left, while the cluster of preview windows below reveals frequently visited sites. The numbers on the opened tabs can be used with the Control key to bring them to the foreground quickly, and you can make a tab an app tab by dragging it to the left. The larger sites in the middle are those that you visit most often. Hovering over a thumbnail will show the full size of that site in the background. Click it to pull it into the foreground and hide the Dash.
A search box appears in the upper left of the browser, which uses an agnostic approach towards your query. It searches your history, opened tabs, and the Internet at large simultaneously, much like the URL bar does now in the Firefox 4 beta but without such strict delineations between sources. You can specify a search engine to use by clicking one of the icons below the search box.
Home Dash is a restart-free add-on, so you won't have to close the browser to get it going. It also only works in Firefox 4 betas 9 and 10. To return to the default interface, you currently must go into your add-ons panel and disable it. Coming in version 2 the developers plan on including a hot key toggle to quickly jump between the two looks.
As befits such a minimalist interface, there are a number of hot key combos to minimize mouse work in the menu. When the Dash is closed, the hot keys function as they normally do: Control + L will bring up your location bar, Control + T opens a new tab, and Control + K opens your default search engine in the current tab. They all open the Dash, too. When the Dash is already open, Control + L will paste the current URL into the search box if it's empty, or select the text that's in the box if it's not; Control + T toggles whether the selected page opens in the current tab or a new tab; and Control + K activates the default search and then cycles through the search engines.
Mozilla has created a lengthy list of keyboard shortcuts for the add-on, including some keys that have double-mapped so that you can use either your left or your right hand. The full list is available in this Mozilla blog post.
Because the add-on is experimental, it wasn't exactly surprising to me that it crashed my browser multiple times, even with only two tabs open. It also had problems rendering thumbnails for the Dash unless I hovered the mouse over them for about 10 seconds. Let me know your experiences with Home Dash in the comments below.
Watch a Mozilla-produced video on how to use Home Dash here.