With graphics set to "Fast" in the video settings menu, leaves that you hold in your hand still appear transparent, even though leaves are supposed to be filled in with black like they are when they are placed.

In the attached video, you can see that the leaves I hold are transparent, while the leaves placed are filled in. My graphics setting is on fast.

This might be fixable with a texture pack, because I've seen texture packs that change leaves on fast graphics. But I used that and it was still transparent when I held it.