This is a long-running problem that I have seen evidence of after the fact but today for the first time I have seen it occur in real time and can make it happen at will. But I can not find a solution or even a discussion of the problem.
Background: We are using AutoCAD 2011. We construct our full scale models in model space and our drawing sheets with dimensions and documentation on layout tabs. We use viewports of course but some sheets only have notes and no viewports. We use many layers, some are turned off or frozen normally unless needed to make special plots. Our drawings are complex but well ordered. Here is the problem:
On any layout tab. I select an item on a layer, could be anything, click layiso to isolate that layer, click layuniso to unisolate the layer, and now, magically, the layers that are normally turned off or are frozen are now also frozen in VP Freeze. I did not intend for them to be VP frozen, I did not command that they be VP frozen. So as a result if I turn on or unfreeze layers that were turned off or frozen during my normal choices, because they are now also VP frozen they will not appear.
I only use VP Freeze within viewports, natch. But this layiso/layuniso activation of VP Freeze creates rogue VP frozen layers on the layout tabs outside of viewports and causes issues when editing is complete and the drawing is submitted for release.
Why would layers become automatically VP frozen after the typical use of layiso/layuniso when they were not intended to be frozen or purposely frozen prior to the layiso/layuniso action? And, man, let me tell you. Now that I know how to invoke this AutoCAD error, I can do it repeatedly and at will. I want this to stop. How can I make this stop?