Editing a sign should check the angle you're looking at it and if it's closer to the front it should edit the front, while closer to the back should edit the back. Currently this does not work.
See screenshot, current facing the front, but editing the back
Code Analysis found here by @unknown
Based on code analysis by @unknown, it appears as though the current code to check which side of the sign the player is facing assumes that all signs are centered in the block, which is not the case for wall signs. Therefore, if the player walks against the wall on which a wall sign is placed, they can edit the back side since they are now over the center of the block.
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