IE provides in the view menu the option of displaying the source code of the page being viewed, I cannot find this function in firefox
That would be helpful except that it does not open the page in the external page source editor that I have set in config. It still opens it in the default Firefox page source viewer which is lame and useless for editing!
You can first open the source code in a Firefox tab with the view-source: protocol and then use View Page Source (Ctrl+U) to open the source in the external editor.
That does not work, at least on my installation. It merely opens the source page in a second Firefox source viewer window and not in an external editor window. I have the path to my Notepad++ escaped as suggested elsewhere but it does not get called or opened.
As Cor-el said, it is working now.
that worked. No changes that I made in about:config seemed to make much difference but editing prefs.js directly as you suggested (for 64 bit Windows 7):
user_pref("view_source.editor.path", "C:\\\\Program Files (x86)\\\\Notepad++\\\\Notepad++.exe");
The config file shows the path to Notepad++ as being identical to what I had already entered! That entry is and was: C:\\Program Files (x86)\\Notepad++\\Notepad++.exe
It is ironic that entering it in Prefs.js made it work but putting it in via the about:config page did not. Of course in prefs.js there are two back slashes for every one shown above.
Oh well, at least now it works.