handle last line of copying lines.

src/vs/editor/contrib/linesOperations/copyLinesCommand.ts

@@ -54,7 +54,7 @@ export class CopyLinesCommand implements ICommand {
 		}
 
 		if (this._noop) {
-			builder.addEditOperation(new Range(s.endLineNumber, model.getLineMaxColumn(s.endLineNumber), s.endLineNumber + 1, 1), '\n');
+			builder.addEditOperation(new Range(s.endLineNumber, model.getLineMaxColumn(s.endLineNumber), s.endLineNumber + 1, 1), s.endLineNumber === model.getLineCount() ? '' : '\n');
 		} else {
 			if (!this._isCopyingDown) {
 				builder.addEditOperation(new Range(s.endLineNumber, model.getLineMaxColumn(s.endLineNumber), s.endLineNumber, model.getLineMaxColumn(s.endLineNumber)), '\n' + sourceText);