This problem happens when in Edit Tool Table.

2021.08.12 Software

I set the axis coordinates in Toolchange Position under the Tool Change tab,and click Update followed by OK.
When I return to check what I have entered, I find the Toolchange Position coordinates have reverted to zero, but the values have been relocated as a Tool Offset under the Offset tab.

If this is correct behaviour, then can someone please explain how it works.

Thanks. Martin.