This issue is very old and still hasn't been fixed. When you destroy a block in creative mode it isn't supposed to drop an item. When you punch out the bottom part of a door it doesnt, but when you punch the top part it leaves an item behind. This has become very annoying.
Linked issues
duplicates 1
Comments 2
It has indeed been fixed in 1.4.3.
Please try and search before you report.
Duplicate of MC-20
Says it's fixed in 1.4.3pre.