pfx,
Let's give it another shot.
"Just to clarify, I want to put a series of buttons on a master slide so
that when I mouse over a button a label/text box will appear in another
place on the master slide that will explain what the button relates to.
This is basically a navigator that will allow the user to move from one
presentation to another presentation. For example the Master slide will have
the buttons M, P, P, F, T, M. When each is moused over it will display its
companion label from one of the following: Metro, Projects, Process,
Finishes, Technical, Misc."
If you want to display text when mousing over a button of the master slide
you could do the following on the master, draw a rectangle or any other
shape, choose Insert - Hyperlink - browse to the presentation you want to
hyperlink to, now click on the screen tip button, top of the dialog and type
the text you want to be appearing when you mouse over it. Repeat the process
for the other buttons.
"If any of these buttons are clicked, it will activate the relevant
presentation already sitting in the background. Being a Master slide I want
these buttons to be visible on all of the 'Show' slides and I will be
duplicating these buttons on the Master slides of the other presentations so
that the user can move freely around regardless of which slide of any of the
six presentations they happen to be on."
As these buttons are on the master of all the presentations (as you claim),
they will allow the user to freely move from one presentation to the other
and back. Yes, but when you jump from one presentation to the other using
your buttons it will bring you back to the beginning of the presentation and
not to the slide last viewed. Can't test it here but that is what will
happen I think.