Add grave gui screen(open at right click with shovel)
Also try to allow to use any type of shovel(even from another mods)

net.minecraft.util.ReportedException: Updating screen events
at net.minecraft.client.Minecraft.runTick(Unknown Source) ~[Minecraft.class:?]
at net.minecraft.client.Minecraft.runGameLoop(Unknown Source) ~[Minecraft.class:?]
at net.minecraft.client.Minecraft.run(Unknown Source) [Minecraft.class:?]
at net.minecraft.client.main.Main.main(Unknown Source) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_60]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_60]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_60]
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_60]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_60]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_60]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_60]
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_60]
at net.minecraftforge.gradle.GradleStartCommon.launch(Unknown Source) [start/:?]
at GradleStart.main(Unknown Source) [start/:?]
Caused by: java.lang.StackOverflowError
at net.minecraft.nbt.NBTTagCompound.copy(Unknown Source) ~[NBTTagCompound.class:?]
at net.minecraft.item.ItemStack.copy(Unknown Source) ~[ItemStack.class:?]
at net.minecraft.inventory.Container.slotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.retrySlotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.slotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.retrySlotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.slotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.retrySlotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.slotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.retrySlotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.slotClick(Unknown Source) ~[Container.class:?]
at net.minecraft.inventory.Container.retrySlotClick(Unknown Source) ~[Container.class:?]

Add configuration option to allow to open graves without shovel in hand.

That would be so cool to have an interface for the graves for 1.7.10. It would make graves compatible with WorldGuard, Factions and other protection plugins.