Pasting text always creates unwanted blocks!?

When I try to do the following:

  1. Add new Paragraph block
  2. Copy some text from my text editor
  3. Place cursor in Paragraph block and paste copied text
  4. I expect to be able to copy any text I want into a paragraph block

But Pasting text always automatically creates unwanted blocks!?

Possible Solution

When writing articles using sakura editor, using no wrap! It solved my problem at the moment but I am sure there are real solutions to this problem.