Default value of from/to property of NumberAnimation should not be 0

Expected:

In the property editor, assigning 0 to from/to property of NumberAnimation should works.

(0 should be blue color in the property editor, and the related QML code should be generated)

Current:

In the property editor, assigning 0 in from/to property of NumberAnimation doesn't work.

(0 is assumed the default value in the property editor, but 0 is not the default value of from/to properties apparently)