It was a cache issue. Clearing the cache solved the problem. Sorry for yhe false positive.
Thanks for your replies and attentio .
... is definitely a bug. Did not happen for the first time that I clicked CLOSE instead of SEND. Especially because the color is so much more attractive. Please move the CLOSE button somewhere else.
To be honest I think the close button should move next to the maximize button. @baris, what do you think?