Quoting of selected part of post which consisit of new lines

Steps to reproduce:
1) Create new post with new lines like this:
First line
Second line
Third line
2)Select just two first lines
3)Press the button 'quote' in this post

Expected result: answer page appears with selected part of post between <quote> like this:
First line
Second line
Actual result:answer page appears with selected part of post between <quote> like this:
First line Second line