i did the same once
and after the integration of the Free Download Manager once again , it happened again,
i discovered that saying no to the Free first dialog, and once looking like closed the download, it suddenly appears the option of saving normal in Windows.
π
The question was that the Free Download saves it as php or something, the way to do is to change in the options , the name to : --whatever-- .skp
Then it works ok.
I use both now π)