I am probably using the wrong term. I was meaning the 'Tree View' where it shows the 'Labels and Attributes', then 'Application', then 'Body' and under that, the constituent components that make up the body.
I have created a model by adding the parts in a logical (to me) way under the main body. As it contained multiple similar parts, I started to rename the components (pads, Fillets, Polars etc) to make them more understandable.
I then started to make changes after printing early prototypes and deleted some of the items from the middle of the list (or at least not the end). I then found that when I saved and re-opened the model, the polar patterns after the deleted item had lost the plane that they were attached to, and so their sketches were 'floating' in mid air on the original plane of the object.
One suggestion to resolve this was to 'recalculate' the entire model. I right clicked on the 'Body' and selected 'Mark to recompute' and a green tick appeared, but the errors were not corrected.
The only solution I have found is to delete everything beneath the original deleted object and add them again. I am hopeful this is not the correct solution otherwise it makes FreeCad much less useful a tool.
As with my other post you kindly helped with, I know I need to read the surrounding information on this bug, but have not had time to do so yet.
I think I need to go back to basics to understand the way that FreeCad builds these objects and 'best practice' when creating a model but need to find a resource to help with this and the time to use it.
With best wishes,