TagScript caches the tags it generates in a ThreadLocal. At the beginning of run() it checks to see if the context wants to cache tags - if not, it clears the cache and regenerates it.
But there is no corresponding check and cache clearing at the end of run(). So if a tag holds onto some significant resource, that resource will hang around until the thread goes away or until the tag is run again.
I am using Jelly Swing extensively, and various tags end up attached to the AWT Event thread for the lifetime of my application.
As a quick fix, I have a patch that simply repeats the check-and-clear-cache behavior at the end of TagScript.run(). I also have a patch that adds this behavior to StaticTagScript, whose run() never seems to clear cached tags.
I am probably just unclear, but it seems to me that there is a deeper issue as well - the context is being asked whether it wants to cache tags, but the result of this question affects the TagScript, which is really independent of the context. It seems like if context wants to cache tags, perhaps the ThreadLocal used for their storage ought to belong to the context somehow.