I have a simple inventory database, where I want to use a button to set a field to either allow modification, or deny modification acording to the previous state. I just can't find a way to script the allow or disallow modification of a field. Am I completely missing it, or is it trickier than I first thought?

You need another field to record the previous state.

Then you can test the value in the field using an IF step in your script.

You could also use the field to change the legend on your button!

I am sorry, I was probably not clear. I do have a field to record the previous state. What I have so far is a script that is run from a button that when clicked, changes from modify mode to lock mode. In lock mode, I change my field text color to red, in modify mode, it changes back to black. That is all working great. All I need is a script command to lock one particualar field in a form, so that it cannot be edited. Essentially the same as checking and unchecking the "Prohibit modification of value during data entry". The other option I thought about is having two fields overlayed, one that is locked, and one that you can edit. But I don't know the command to show/hide a field. Hope this all makes sense.