Windows/Mac/Linux: Mozilla's second Developer Preview of Firefox 4.0's framework and back-end highlights a feature we'd heard was coming: separate processes for plugins. That means if (when) Flash or another plugin crashes, there's a good chance your browser won't go with it.
This second alpha of Firefox 3.7 — which is, confusingly, what will actually be released as 4.0 — adds some performance improvements and HTML5 efficiencies, but the main new thing is the "out-of-process" plugins. Contained, stand-alone processes for each tab and add-on are likely in Firefox's future, but starting off with the most likely crash candidates is a good start.
Those interested in kicking the tyres really hard on Flash crashes and reporting back to Mozilla should give it a go, as should anyone developing extensions or testing site compatibility.
This Firefox developer preview is a free download, available for Windows, Mac and Linux systems.
Mozilla Developer Preview Now Available With Out-of-Process Plugins [Mozilla Developer News]