A control has a text field which can be formatted using DecimalFormat, the format string can be set with a styleable property. In this scenario this property is set via setStyle(). This works initially, but as soon as totally unrelated classes are removed from the control, the styleable property reverts to its initial value, but the style string is unchanged!

This behavior is introduced in 8u20 and still present in 8u40, in 8u00 it works as intended.

To quickly see this in real life: checkout JFXtras labs from github, open the project in an IDE, and start the SimpleMetroArcGaugeTrail1 class. It's the gauge with the "W" in the text, at first.