See http://ubuntuforums.org/showthread.php?p=6391989#post6391989 Rather than remove all customisation by uninstalling firefox or deleting localstore.rfd, my workround was
close firefox edit ~/.mozilla/firefox/<profile>/localstore.rdf to remove the 6 lines referring to "sanitize.xul"
<RDF:Description RDF:about="chrome://browser/content/sanitize.xul#SanitizeDialog" screenX="439" screenY="345" /> <RDF:Description RDF:about="chrome://browser/content/sanitize.xul"> <NC:persist RDF:resource="chrome://browser/content/sanitize.xul#SanitizeDialog" </RDF:Description>
then restart. The repeated dialogue goes away.
See http:// ubuntuforums. org/showthread. php?p=6391989# post6391989
Rather than remove all customisation by uninstalling firefox or deleting localstore.rfd, my workround was
close firefox firefox/ <profile> /localstore. rdf to remove the 6 lines referring to "sanitize.xul"
edit ~/.mozilla/
<RDF:Description RDF:about= "chrome: //browser/ content/ sanitize. xul#SanitizeDia log"
screenX= "439"
screenY= "345" /> "chrome: //browser/ content/ sanitize. xul"> "chrome: //browser/ content/ sanitize. xul#SanitizeDia log"
<RDF:Description RDF:about=
<NC:persist RDF:resource=
</RDF:Description>
then restart.
The repeated dialogue goes away.