JTextPane using WrappedPlainView does not wrap the last line of a multiline text

JTextPane using WrappedPlainView does not wrap the last line of a multiline
text under a certain condition.

[Reproducer]
  MyTextPane.java
  sample.txt

[Reproduction procedure]
(1) Start MyTextPane.
  $ java MyTextPane
(2) Enter Return key to input a new-line code in the JTextPane component.
(3) Open sample.txt and copy all the text in sample.txt to clipboard.
sample.txt contains 3 lines and only the last line does not end with a
new-line code like the following:
  --- sample.txt ---
  aaa...aaa<NL>
  bbb...bbb<NL>
  ccc...<EOF>
  ---
(4) Paste the clipboard-copy in the JTextPane. Only the last line ¿ccc...¿ is
not wrapped.

The last line ¿ccc...¿ should be wrapped as well as the other long lines
(¿aaa...¿ and ¿bbb...¿ line) in the pasted text.