Comment 2 for bug 630614

This has been fixed and committed to the trunk. The scrollbars were not being adjusted correctly as the screen is resized. The "pagesize" property of the scrollbars needed to be updated to the size of the timeline window. This also fixes some other related bugs, such as dragging and dropping clips on a large (scrolled) timeline, and they sometimes appear in the wrong spot... or have a big offset from the mouse cursor.