You cannot pass flick() an icon object to use. While this isn't contradictory to the reference entry, it is unexpected. Also note that it does work with image objects.
Code Snippet (if applicable) to Reproduce Problem:
An icon object can be used to flick() an icon
Using flick() with an icon object has no effect
Does the problem occur:
Every time? Or how often? Every time
In other games? Presumably
In other user accounts? On administrator
On other computers? Unknown
When does the problem NOT occur?
When passing an icon reference with single quotes [such as flick('icon1.dmi',src)], when passing an icon_state in the target's icon, or when passing an image object.
Did the problem NOT occur in any earlier versions? If so, what was the last version that worked?
Use an image object instead