Lock Material Output Nodes on X Axis

Especially with "insert offset", It often happens that as you build a Node Tree, the Material Output Node gets moved further and further away from it's origin and before you know it, you built a gigantic Nodetree but it has migrated to Buxtehude. This is especially annoying when you switch between Materials and the Nodetrees are in totally different places on the Grid and you have to press A + , to find it again.

The solution I propose for this is to lock the Material Output Node on the X Axis of it's origin. Insert offset should then move the other Nodes relative to the Output Node.
I'd lock it on Y too, but I guess this can't be done since one might have multiple Material Outputs for different Renderengines etc.