You can use this JSfiddle https://jsfiddle.net/s4c87msq/27/ and try the following examples:
1. Copy A2 to B2. B2 is now editable... I'd expect the copy to be ignored for the non-editable destination cell B2.
2. Copy row 1 to row 2. Row 2 is now fully editable... I'd expect the copy to be ignored for the non-editable destination cell B2.
3. Copy some text from elsewhere outside the spreadsheet and paste into one of the non-editable cells. The cell content is changed (but it is still non-editable)
Using 2016.1.412 version.