Can't select objects in model space for unknown reason.

[Anonymous]

I cannot edit objects in model space for an unknown reason.  I'm trying to edit model space objects in a specific tab.

Here are some details about my plight:

-The objects I'm trying to work on can't be highlighted in paper space or model space (they're supposed to be in model space).

-The viewport is highlighted blue when in model space and I can't deselect it for a specific tab only; all other tabs are normal and I can edit model space objects without issue.

-When unlocking model space to zoom in or out, the objects in the viewport do not change size.

-The objects I want to work on are definitely thawed and unlocked.

[cadffm]

Two viewport?

Move  the one you know about, can you see a second one?

[cadffm]

Or is this object not created by you, tge whole file not from you?

Perhaps you have an Inventor view in you layout.

Upload a sample file and we can check this.

[rkmcswain]

Are layer 0 and/or the DEFPOINTS layer involved?

Go to Options and make sure you don't have any hidden dialogs, then reopen the drawing.

F2 then study everything that printed during the open. Perhaps these are proxy objects? 

[pendean]

show us, post your DWG file.