Multiple text fields within template gives issue

There is a defect that when typing in to text fields in a form based on a template itself made of several text fields. It seems to be a JS/wicket defect.

If one edits a document of the type Projecten and then make a new item of the type Materiaal/Producten. it then goes wrong when you try to insert text in to the second field of a new item. De text just disappears after typing a few letters. That's strange given that the template Materiaal/Producten is made of four objects of the type string, nothing really exciting. Given that the template is only made of text fields and the CMS does not use any specific plugin I suspect that this error belongs to the CMS and is not specific to that of the project.