Created attachment 938791 [details]
View of the bug : impossible to select

Description of problem:
in the menu tool, there is 'import' function in order to import old mails from thunderbird.
On the first window, we can choose the option (all messages; only messages, only contacts,...).
Then on the second window, we must choose the source but it is not possible (cf screenshot which is enclosed)

Version-Release number of selected component (if applicable):
Thunderbird v.31.1.0, released: September 2, 2014

How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info: