I am currently facing an error with the Experience Editor and integer field.
So I have a Datasource template that has a field of integer type (without validation - meaning not required). Through the Experience Editor I create a new Datasource Item based on this template.
Rendering and data show as expected and, by default, this field is empty - which again is fine.
However if I save the page I get the following error:
I do understand that it is because of the field being empty and therefore string empty is not a number, but this field can be empty.
If I put a number in, saving works as expected.
This happens with Sitecore 8.0 (rev. 150427)