When using left+right mouse at the same time, players can replace the block they are looking at. The problem is that anything placed on top of the replaced block (redstone, repeaters, etc.) is deleted which can be annoying if you just want to swap a few blocks without selecting them and replacing them with Worldedit. I don't know how hard it would be to add a gamerule that prevents this behavior, but it would be a nice addition

could you create a feature request on our discord?