Out of curiosity, I downloaded the latest version of Celtx (2.7) for Windows to see how it would handle importing and formatting All About Eve and Celtx was worthless. When I did the typeset/PDF all it shows is 1 or 2 pages, sometimes just the title page, in spite of the Script view showing all the individual scenes including in the left sidebar list of scenes. And a print preview showed sluglines e.g. isolated at the bottom of the page with the next pages showing the first action lines, viz. orphaned sluglines. Celtx? No thanks.
Celtx. I've tooled around with final draft and found it not worth the cost at all when there's software out there that can do everything I need for free.
Used both FD and Celtx and am moving to Celtx - it's not as quite good as FD for screenwriting, but it's close. If I were just writing the screenplay, I'd use FD...but if you're writing the screenplay & making the film, the ability to tie production elements to the screenplay is just awesome and outweighs the shortcomings Celtx has with regards to its interface for screenwriting.