Bill wrote:

"You don't really want to eliminate the 'new_tool.dat' results. This file
exists because some toolbar buttons have been added with some of the
updates."

OK, OK, I wouldn't do it again (at least not without a little editing...)
In fact I started to notice the problem because I used to turn the 'Zoom out
four levels' action into a 'Zoom one level' one, something lost between
updates. Then I started changing the button icons too and they also
vanished!! That was too much to repair and decided to implement the Big
Replacement Routine. No problem. Now I know why things are like they are.
And that's enough for me.
Many thanks.