Funny Scroll Wheel Behaviour When posting

When you open the posting console to compose/ edit a post, the mousewheel scrolling has some funny behaviour:

-It still scrolls the page behind it, that should no longer be in focus or under the cursor?

-However when the message within the console it is long enough it will scroll that content, but when you reach the top of scrolling your message, scrolling focus can seem to go back to the page behind.

Can the focus be fixed to the posting console, when cursor is there?