Hi Brian,
Here is the problem: some appearances aren't exclusive, like having character counter and the resizing, while others are exclusive, like a dropdown and radio buttons. Right now, Form Builder doesn't know what appearance can be used with what other appearances, and thus doesn't let you add multiple appearance. Until we have that mechanism in place, the current behavior seems to be the safe thing to do. And of course, this doesn't prevent you from changing the source of the source to have multiple appearances you know to be compatible.
Alex
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