Editable Table Converter?

Hi,
I have a table with an converters set onto one column.
If I set the table to editable, then I got ConversionException even if there is a converter set!

Try the example from https://vaadin.com/de/wiki/-/wiki/Main/Formatting+data+in+Table/pop_up
and set the table to editable.

Is this a bug? Or what am I doing wrong?

Regards