Object In Non-Existant Layer

I realize I probably created this problem.  I created a new file from the template I've been using, which is based on the AutoCAD files my architect has been sending me.  Then I copied part of a diagram from a new file he sent me (one which I had trouble importing, by the way - It was a .dwg file, but when I tried to import it, LibreCAD would lock up for a long time with the wait pointer going, so I loaded it into DraftSight, saved it as a .dxf file, and then I could load it).  Once it was copied from the imported file, I went to my file, based on my template, and pasted it into that file.

Now I'm trying to move some objects.  Whenever I do, even if I haven't selected them, some other objects move with whatever I select.  In the past when this has happened, I just hide that layer.  In this case, clicked on Properties on the dock, then picked the object I was having trouble with - the one that would get selected with anything else.  I looked at the layer and it lists that as being in a layer that doesn't even exist in my Layer List.

Is this because of something I did?  How can I hide that layer or lock it down?

Maybe the drawing or parts of it have been imported as a block. Are the not wanted objects highlighted too when picking the wanted? Try modify - explode to disassemble the block.
More advanced cad systems like autocad have the feature to integrate several drawings with different scale into one drawing. For example the normal floor plan could be 1:100, a more detailed bathroom with all the tiles 1:20 and layout objects like the paper frame or a diagram would then be 1:1. I don't know how Librecad handles this if such a drawing is imported. Anyway it gets complicated then and your problems could have to do with that.

if I select anything else, I can select exactly what I want.  But if I select anything with a rectangle, those parts in the non-existent layer will always be selected along with anything else.

I used a selection rectangle over an empty part of the drawing to select nothing at all and it selected the parts in question.  I picked Modify->Explode, and now the issue is done and the parts are in a normal layer.


Thanks!