ActiveX Textbox Shrinking!

Hi - I have created an active-x textbox for users to input comments, but once you are done typing in it and click elsewhere in the sheet, the text in the box drops in size.
Then when you click and type again in the box, it drops in size again. This continues until the word are no longer visible - does anyone know how to fix??
Thank you !!

Just added a list of the properties currently selcted in case someone can help better with that info...

thanks again

textbox.help.properties.PNG