As the Omniscient Browser Toolbox progress, the Browser Content Toolbox becomes useless.
This toolbox is the one you open from "Web Developer" Menu and "Browser Content Toolbox" entry.
It opens a special toolbox, with just the console, debugger and memory, which are debugging the content process into which the current tab is running.
The Omniscient Browser Toolbox allows to debug the parent process and all the content processes, all at the same time, in a unique Toolbox. This makes the Browser Content Toolbox irrelevant and unecessary limited.