JA+ client side mod can directly interfere with the custom screens for those with both Jedi and SITH customisation skin packs, for me it took out an entire tab of Jedi customs (this can mean you lose a whole section of either unique heads or robes/legs - the model will still exist but you wont be able to select it because that entire section has disappeared).
Luckily there's a simple fix, go to your Game Data folder and open up the japlus file. Open the clientPlugin_v*.pk3 (v1.4b4 for me) with WinRAR and double click on 'models'. In the models folder there's a subfolder called 'player' that contains a buggy custom skin, this is the useless tab that directly overrides one of the customisation screens, simply delete the 'player' folder inside 'models' to get some of your customisation back
don't worry, this won't have any negative repercussions in game and online I have already tested this.
Hopefully I was clear enough, if you have any questions ask away and I'll do my best to help
oh, and I believe those with JA++ and JA unlimited won't have this problem.