This is the same as JDK-8149622 but for a editable comboBox. 

To reproduce, use the example in that report and set the combo's editable property to true. Compile, run, press Enter in textField and note the printed sequence of filter/handler notification

expected (same as with a not-editable combo)
- scene filter
- combobox filter
- combobox handler
- scene handler

actual
- scene filter
- combobox filter
- scene filter
- combobox filter
- combobox handler
- scene handler
- combobox handler
- scene handler

which is similar to the broken sequence before the fix, but worse: now the scene filter/handler are both called twice.

P3 because I think there's something severely wrong in event dispatch around textField/combo which seems to be hard to tame. A similarly confused event dispatch sequence can also be seen in an example with a plain textField only - https://stackoverflow.com/a/51419618/203657  (which was triggered by digging into JDK-8207759)