LibButtonGlow-1.0 is a replacement for the ActionButton_Show/HideOverlayGlow APIs.
Using the built-in APIs will irreversibly taint the Action Button functionality, which is why it should be entirely avoided. The resulting taint is hard to track and pin-point exactly, resulting in action blocked messages when switching stances or using vehicles.
Unfortunately, even using Blizzards XML template can cause taint and will break the Action Buttons under certain circumstances. LibButtonGlow-1.0 does not use the Blizzard template, and instead offers a clean implementation in Lua only.
This library offers a simple drop-in replacement API to resolve these issues.