[Pharo-users] What happens to saved inspectors?

Hello I am using Moose 5, which is essentially Pharo 3, downloaded late December 2014. I have a development project which mainly consists of a collection of workspaces and inspectors (I really do intend to turn it into a properly structured set of classes one day!). I have noticed that, whenever I save an image with some inspectors open and then reopen the image, the title bars of the inspectors have become red rectangles with a cross superimposed. Often I can work out what the title should be and carry on, but in many cases all I can do is close down the inspector and reopen it. Is this a known problem, and is there any way to work round it? Thanks for any help Peter Kenny