As I've explained in the Bug Description, before filling this bug, I'd tested the same process in my wife's laptop then with 'Ubuntu 16.04 LTS' and it imported the certificates ('.cer' and '.p12') without issues. But in my laptop with 'Ubuntu 18.04 LTS' the problem exist (greyed button).
Therefore, there are two possibilities: 1) I'm mad or a liar; or 2) the statement on comment #15 is wrong.
I may well be mad, but not a liar! But the experiences described on comments #21 and #24 corroborate to the second possibility, i.e., that the statement on comment #15 is wrong.
As I've explained in the Bug Description, before filling this bug, I'd tested the same process in my wife's laptop then with 'Ubuntu 16.04 LTS' and it imported the certificates ('.cer' and '.p12') without issues. But in my laptop with 'Ubuntu 18.04 LTS' the problem exist (greyed button).
Therefore, there are two possibilities: 1) I'm mad or a liar; or 2) the statement on comment #15 is wrong.
I may well be mad, but not a liar! But the experiences described on comments #21 and #24 corroborate to the second possibility, i.e., that the statement on comment #15 is wrong.