Thanks a lot for your reply.

1) What do you mean by "... directly dropped into..."?
I mean "Drag and drop"

2) What encoding is the open document into which you paste? Is it any of the Unicode encodings (e.g. UTF-8)?
Western European (Windows)

3) What was the encoding of the source from where you copied the text? Was it Unicode? Was it of the same or a different encoding than the one you pasted into?
I don't know the encoding of source. My EmEditor was setting as detect both Unicode signature and UTF-8. When I pasted the copied text or "drag and drop" the selected text, the encode did not change in the both.

Any idea about this?