Firefox did not report that it needed to be restarted

Binary package hint: ubufox

After having done an update, when I went to open a new tab in Firefox I got this error message:

Assertion failed

ASSERT: *** Search: _installLocation: engine has no file!
Stack Trace:
0:ENSURE_WARN(false,_installLocation: engine has no file!,2147500037)
1:()
2:()
3:()
4:epsGetAttr([object Object],alias)
5:()
6:SRCH_SVC_getEngineByAlias(wiki.canonical.com)
7:getEngineByAlias(wiki.canonical.com)
8:getShortcutOrURI(wiki.canonical.com,[object Object])
9:canonizeUrl([object KeyboardEvent],[object Object])
10:handleURLBarCommand([object KeyboardEvent])
11:anonymous(textentered,[object KeyboardEvent])
12:fireEvent(textentered,[object KeyboardEvent])
13:onTextEntered()
14:handleEnter(false)
15:onKeyPress([object KeyboardEvent])
16:onxblkeypress([object KeyboardEvent])

And I didn't know why. Only when someone pointed out to me that I needed to look at the lightbulb icon, did I know why I was getting this error message. Which explained:

Firefox-3.0 restart required

Firefox-3.0 has been upgraded (or reinstalled) and must be restarted. Please quit and restart your web browser now.

Would be much easier if the pop up included this info, rather than the tonne of weird text above, better still it would be great not to have to restart FF at all.

Please see attachment also.