This is the technical support forum for WPML - the multilingual WordPress plugin.
This thread is resolved. Here is a description of the problem and solution.
Problem: I am trying to translate a string with string translation but the field is not editable. Solution: This is the intended behaviour. The string you see is just a placeholder and cannot be edited. That placeholder is used to show that, if nothing is added in the translation field, then that will be the value used.
If you wish to start the translation from the original value, you can copy the original value and paste it there.