How to lock every item of a prebuilt house

[Silverfish Tigerfish]

I have just bought a house, fully furnished, rezzed and placed as a sky box. I have been locking the parts of it but still manage to accidentally click on walls and end up returning parts of it. Is there any way to lock all items on my land before rezzing other items?

[Lindal Kidd]

There's no automatic "lock all" button, but you can select multiple items by simply dragging out a selection box around them.  Then you can lock everything that you've selected.

If some items are already locked, and others not, the Lock box will have a faint gray check mark in it.  Click it twice, or until the check mark looks solid.