Copying and pasting content into Code Block Macro is not working in IE11

If you add a code block macro on a page and try to paste content from another area (like notepad) the content will be pasted under the code block instead of inside it.

Steps to Reproduce:

1. Start a confluence 5.6.5.
2. Access confluence from IE11.
3. Create a page.
4. Add a code block.
   
   Note that the cursor is inside the codeblock.
5. Now go to notepad and copy some content (using CTRL+C for instance).

   GIT stuff:
   add
   commit
   checkout
   

6. Go to your confluence page and paste the content (CTRL+V).
7. The content will be pasted under the code block.
   

Workaround:

Just add a character into the macro before pasting the content:

Then paste the content: