Currently Being ModeratedOct 28, 2013 7:06 AM (in response to patrickrobinson)
Go to File>Export>Version and click the pop-up menu opposite to Name Format, then select Edit or any name format selection you wish. Upon selecting Edit, the entry opposite Custom Name will become editable.
I hope this helps.
Currently Being ModeratedOct 28, 2013 10:13 AM (in response to jfa643)
I have the same bug (Mavericks + 3.4.5). I can set the cursor in the 'custom name' field, but the keyboard does not do anything. Only after some time (?) or clicking random things can I enter or edit the name. A wierd thing this.