Yes, this button was hidden off-screen as the customization feature doesn't do everything we want yet. Being able to find it by varying browser zoom was a bug, which has now been fixed.
Customized Avatar screens have been returned to normal and plat spent on customizing has been refunded.
While technically this was an exploit the end result was very minor, no hard feelings. In the future if you find a "hidden" feature you can always PM it to me before posting, I'll let you know if it is intended.
I'm glad you are excited about customization! =)
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