bug with placeholder

Hi Everybody!
I’m using this plugin and it works very well.

But if in the code, I put the placeholder, it doesn’t work.

For example: if my tag is this:
[dynamictext email “CF7_GET key=’email'”] , it works good.
But if I modify this tag to this:

[dynamictext email “CF7_GET key=’email'” placeholder “Your email”]

It doesn’t work.
Why?