Last updated: before December, 1998
If you are using v3.0* you can set a design mode password by selecting the Tools/Preferences/Password menu item. Approach will then not let anyone in design unless they know the password (even by status bar, icon or key combination).
Read on if you are using v2.1, or if you would also like to remove the temptation of changing the form:
Menus can be customized so that the design environment option never appears. Apparently, custom menus are kept in .APR files so that no custom files on user PCs would be required.
Icon bars can be customized so the design environment icon never appears.
The status bar on the bottom of the Approach window will let the user go into the design environment. The status bar can be suppressed but this prevents the user from reading useful information such as current record number and how many records were found out of how many. There are no Approach macros and formulas that support display of such record information on a form.
In v2.1 there is no way to prevent a user from getting into the design environment via CTRL-D.
.APR / .VEW files can be made read-only by changing their properties in File Manager, but if a user gets into the design environment, Approach won't tell them they cannot save design changes until they try to save their changes, and they may know how to change the file properties.