NoFrameDrop

It mean that item in the frame wasnot drop unless you break the frame.

 

Use this one https://github.com/kenygamer/iProtector-v4.0
Because that have updated now you can flag TNT
And also protection item frame no drop too anymore
I have test use it my server item frame not drop anymore useful this plugin i decreased one plugin itemcase

 

But I dont want to use iProtect, I had a plugin like that

 

I made a plugin for you: https://github.com/infinity-pe/ItemFrameProtector
You can protect ItemFrames in different worlds.