Either you have extra newlines (the cr/lfs Jim Anderson was talking about) in which case you can just select all the blank lines and hit delete to get rid of the extra space. The other possibility is that what you think is blank space is just the IDE letting you scroll down one page past the end of the file (until the last line of the file is at the very top of the screen). This is to let you scroll to the bottom of the file and start typing without causing the screen to scroll every time you start a new line.
Edit:
A quick glance at the other editors on my computer shows that this sort of thing is common - CodeWright will let you keep scrolling down as far as you want (pages and pages past the end of text) - although it does show the scroll bar as being all the way to the bottom when the bottom of the file is in the middle of the screen of text.
Even basic tools like Query Analyzer have this.