I'm updating my review. Now the plugin works as it should. Everything works as it should. I hope you'll continue working on this project. Thank you.

This plugin is amazing!
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[13:26:57 ERROR]: Could not pass event BlockPlaceEvent to ShopShelvesSpigot v1.0.0
java.lang.NoClassDefFoundError: org/bukkit/block/data/type/Shelf$SideChain
at ShopShelvesSpigot-1.0.0.jar/me.andy.shopShelvesSpigot.logic.ShopHelper.lambda$setShopMode$2(ShopHelper.java:92) ~[ShopShelvesSpigot-1.0.0.jar:?]
at java.base/java.util.Optional.ifPresent(Optional.java:178) ~[?:?]
at ShopShelvesSpigot-1.0.0.jar/me.andy.shopShelvesSpigot.logic.ShopHelper.setShopMode(ShopHelper.java:81) ~[ShopShelvesSpigot-1.0.0.jar:?]
at ShopShelvesSpigot-1.0.0.jar/me.andy.shopShelvesSpigot.ShopListener.onShelfPlace(ShopListener.java:730) ~[ShopShelvesSpigot-1.0.0.jar:?]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[paper-api-1.21.10-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:71) ~[paper-api-1.21.10-R0.1-SNAPSHOT.jar:?]
at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:54) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.callEvent(PaperPluginManagerImpl.java:131) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:628) ~[paper-api-1.21.10-R0.1-SNAPSHOT.jar:?]
at org.bukkit.event.Event.callEvent(Event.java:46) ~[paper-api-1.21.10-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.event.CraftEventFactory.callBlockPlaceEvent(CraftEventFactory.java:394) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.world.item.ItemStack.useOn(ItemStack.java:443) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.level.ServerPlayerGameMode.useItemOn(ServerPlayerGameMode.java:551) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.network.ServerGamePacketListenerImpl.handleUseItemOn(ServerGamePacketListenerImpl.java:2056) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.network.protocol.game.ServerboundUseItemOnPacket.handle(ServerboundUseItemOnPacket.java:45) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.network.protocol.game.ServerboundUseItemOnPacket.handle(ServerboundUseItemOnPacket.java:10) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.network.PacketProcessor$ListenerAndPacket.handle(PacketProcessor.java:99) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.network.PacketProcessor.executeSinglePacket(PacketProcessor.java:33) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1511) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.MinecraftServer.recordTaskExecutionTimeWhileWaiting(MinecraftServer.java:1229) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1352) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:384) ~[paper-1.21.10.jar:1.21.10-113-9fc21bc]
at java.base/java.lang.Thread.run(Thread.java:1575) ~[?:?]
Caused by: java.lang.ClassNotFoundException: org.bukkit.block.data.type.Shelf$SideChain
... 23 more