FormItem doesn't layout correctly when the label is made shorter or empty

Steps to reproduce:
1. Run the bugfile.
2. Click each button in order and observe the result.

Actual Results:
When one of the FormItem label strings is made longer, both FormItems lay out properly.
When both of the FormItem label strings are made shorter, or set to the empty string, both FormItems lay out incorrectly, with extra space.

Expected Results:
Correct layout when a FormItem label is dynamically changed.

Workaround (if any):