How to increase font size in Adobe Acrobat in multi-line text fields

[Alysée5C48]

I have a problem with the font size in text fields to fill in a PDF form.

For classic text zones I put in "Properties" the font size "Auto" so that it is not very small when the user will fill out the form, but when I integrate a text zone where in "Properties" I checked "Multiple lines" so that the user can write on several lines, the font size becomes tiny despite the "Auto" size that I put. 

Anyone have a solution please ? 

[try67 · Accepted solution]

You can't really change it, but the default font size is not really "tiny". It seems to be about 10 points.