ADDITIONAL SYSTEM INFORMATION :
JavaFX 15 / Windows 10 / Oracle OpenJDK 15

A DESCRIPTION OF THE PROBLEM :
The DatePicker control does not commit/update its value on focus loss.

This bug is related to various other JBS issues but some issues say they are fixed, others do not, some say regression, etc. - it's confusing and I believe the bug may have gotten lost in the shuffle. I apologize ahead of time if this is duplication (feel free to mark it as so or delete it), but I am unable to comment/inquire on the other issues.

https://bugs.openjdk.java.net/browse/JDK-8191995
https://bugs.openjdk.java.net/browse/JDK-8136838

REGRESSION : Last worked in version 8u261

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Type in random alpha characters into the DatePicker Editor TextBox.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The text of the DatePicker Editor is returned to its previously valid value.
ACTUAL -
The random text remains.

CUSTOMER SUBMITTED WORKAROUND :
DatePicker datePicker = new DatePicker();
datePicker.setConverter(new StringConverter<>(){
    @Override
    public String toString(LocalDate value){
        return value != null ? DateTimeFormatter.ofPattern("M/d/yyyy").format(value) : "";
    }

    @Override
    public LocalDate fromString(String value){
        if(value != null && !value.isBlank()){
            try{
                String pattern = value.matches("[0-9]{1,2}/[0-9]{1,2}/[0-9]{2}") ? "M/d/yy" : "M/d/yyyy";
                return LocalDate.parse(value, DateTimeFormatter.ofPattern(pattern));
            }
            catch(DateTimeParseException e){
                return null;
            }
        }

        return null;
    }
});
datePicker.focusedProperty().addListener((observable, oldValue, newValue) -> {
    if(!newValue /** Focus Loss **/ && datePicker.isEditable()){
        LocalDate newDateValue = datePicker.getConverter().fromString(datePicker.getEditor().getText());
        if(newDateValue != null && !newDateValue.equals(datePicker.getValue())) // Set DatePicker Value
            datePicker.setValue(newDateValue);
        else // Revert Editor Text
            datePicker.getEditor().setText(datePicker.getConverter().toString(datePicker.getValue()));
    }
});

FREQUENCY : always