Why when you use form editable grid view

Why when you use the form editable grid view or any other grid form, when you ADD the form stretches out and you have to horizontal scroll? This happens even if I set the pixel width or use 100% width. Please help.

When you are not in editable mode, is just text occupping some space, just text. Once you work with HTML entities, it get the pixels defined in the configuration of the field AFAIR. Then, if you multiply the grow of the field, by the number of the fields…voil?!

Thank you.