Start application with Browser Toolbox (formerly Browser Debugger). Tells the application that it is being launched by the OS shell. Note that on Windows this only works with a redirection such as (bug 355889).
Write messages for the debugging console into the window which launched the application instead of opening a new window for the debugging messages. This option is available only in a command console.
As XPCOM is installed as a module set, it would be counter-productive to spend much time ensuring backward compatibility for something which ships in a complete state, anyway.
Other reasons can be misconfiguration (mainly path errors, where the binary can't find the XPCOM modules to load them) or broken or missing modules.
Command line options are entered after the command to start the application. (This is noted in the option descriptions below.) Multiple command line options can be specified.
In general, the syntax is as follows: The example above invokes the "-Profile Manager" command line option with Mozilla's Thunderbird mail client.
Not one of the search hits I found mentioned checking for old modules left behind from previous installs.
(Apparently, instead of loading the new components from the XULrunner install, Firefox saw a module in the same directory as firefox-bin, and tried to load that, instead (path order, not path error).
In my case, I tried installing several updated versions of Firefox (I started with 4.0.1).If Gecko cannot start, then there is no rendering engine for the application, essentially stopping whichever Mozilla-based app one might wish to run, before it even gets started. Like any other application, XPCOM has various version requirements for its various components.Newer versions are not necessarily compatible with older ones, and are rarely tested for interoperability.This modularization allows XPCOM to be (mostly) platform-neutral, making it possible to run the Gecko rendering engine on a variety of platforms.