When running as Spanish (es) the control correctly shows commas as the decimal separator but see below. The control seems pretty broken when running under Spanish.
1) When I focus into the text box above that started off bound to a value I am unable to change the value by typing more numbers. I should be able to put my cursor in front of "33,300" and type "4" it should result in "433,300". Instead, nothing happens when I type "4". If I delete ",300" from the end the control then allows numeric entry.
2) If I delete the full number and type in a new one I am unable to enter "." or ",". Those keys are being ignored.