So, after weeks and weeks of trying to figure out why the parts compatibilty list won't load when revising or creating a new listing, I have figured out that you must not have any open windows or tabs from previous listings that you have finished editing or listing. You must close any tabs or windows that have been open after your listing has stated that it hs been revised or listed. You may have multiple tabs with different revisions open, and the parts lists may be loading for all of them, but the second you finish a listing and it has given you the "Success!" pop up, you may have issues loading the compatibility list in a fresh revision page for a different listing if you haven't closed the "Success!" page. Also, keeping multiple revision and listing drafts open even if you're not done with them, may keep your compatibility list from loading in the single listing revision page or bulk editor. You may also have to close tabs from other browsers if you're using more than one type of browser.
I also advise reinstalling flash from Adobe to make sure you have the most up to date version running in your browser. I have only noticed this problem with the list on Chrome and haven't tested to see if it's a problem on Firefox or other browsers so you may have to jump through some additional hoops to update flash on them.
