Fixed: backspace on a none editable/enable field trigger the browser's page back button

Previously, when hitting the backspace key on a none editable/enable field, this triggered the browser's back button.
Now it does not anymore.

All credits for @apajarita

Fixed #2189
Merge pull request #2196 from Dogild/BackSpaceTextField

Fixed: backspace on a none editable/enable field trigger the browser's page back button