Comment 2 for bug 491360

for some reason there was a custom entry in the
default mail handler preferences

I did not add this

there were also 2 others one thunderbird (with icon) and
the other mozilla thunderbird (with icon)

I did not add the not properly working custom item nor
either of the 2 available options

install of thunderbird / uninstall of evolution must be causing
this buggy setting of the default emailer ?