Thank you for your help and sorry for the slow reply.
I figured out what the problem was. It was all about the MyMobile theme which seems to have a broken filepicker.
I did some tests with other mobile/Responsive themes and the application selector worked propertly.
I apologize for offending the "poodll assignment plugin" which was not responsible for this problem.
You were right about the s3 tab, there is no native sound recorder installed on it.