Glowing maps in frames

I opened my inventory while I pointed at a frame with a map in it. There were 10+ maps on the wall. As I hovered my mouse over an icon some of the maps changed their brightness.

What I expected to happen was...:
Just the icon in my inventory glows.

What actually happened was...:
Some of the maps in frames were glowing.

Steps to Reproduce:
1. Put some maps in frames on a wall.
2. Open your inventory and hover above an icon.
3. See the maps changing their brightness.