Thanks Fizzio.
This is clever stuff but unfortunately won't solve my problem as there are in fact 24 of these little text boxes and I really don't have the room on the form for another 24 unbound text boxes. (Nor do I want the confusion of all those!)
The heart of the problem really is that, although the user can type any value into any of the 24 "OTDR Index" fields, I wanted them to default to there most common value after the first one is input. ie. if "1" is typed into "OTDR index1" , "OTDR Index2" would = 02, the third = 03 etc.
Because I want a two digit view (ie displaying a leading zero for single numbers) I had to put this code on the After_Update of "OTDR Index1":
[OTDR Index2] = "0" & [OTDR Index1] + 1
[OTDR Index3] = "0" & [OTDR Index2] + 1
etc, etc
[OTDR Index24] = "0" & [OTDR Index23] + 1
This works fine until the first box ="10" or higher because the following boxes display "011", "012" etc instead of "11", "12" etc.
Perhaps there is a better way to automatically increment the values after "OTDR Index1", without using Autonumber and such that the user can overtype any default value assigned if neccessary.
Of course I could just narrow down the size of the field to "hide" the zero but I imagine the user would run into problems if they had to overtype a default value and I'm sure there must be a way to display just the last two digits.
If anyone has a solution I would be very grateful.
Thanks again.
Ali