Spotted something about the beginning and the end
To start with Elizabeth looks as if she is basically mourning the death of someone..as if everything around her the wedding..the dress Is all a sham..and she's really mourning because something/someone is dead and missing from her life. We then find out the wedding gets halted because of a certain Mr Sparrow..Beckett then says "wedding stopped or fate intervenes?" and he then says "you seem to be going through a lot of trouble to ensure Jack's safety" which she snaps back at in denial! BUT she suddenly comes alive..and goes in pursuit of a certain Mr Sparrow..and feelings for him develop..which appears to make the wedding look less and less likely in the future (dress sinking etc)
Later on?
She's mourning again and its because Jack is missing from her life. ..she had the choice to remain with Will and move on in life (drinks handed out as if it was a wake) and she didn't drink..instead she decides to find a certain Mr Sparrow again. Meaning the wedding with Will is never going to happen because she is now has accepted her feelings for Jack Sparrow? She realizes that what she has with Will isnt satisfying..only Jack can fill that void.