Mac Excel - MsForms

I have an Excel Workbook with forms to insert complex datas in multiple sheets.

The Workbook is shared with people using Mac and Win PC

Inside each form there are several Text-Boxes to be filled with datats we often find in other apps (Mail, Word, PDF files) and Mac users are not allowed to copy/paste or drag and drop text in the TextBoxes while PC users can. The property "fmdragbehavior" is set.

Any suggestion ?