Having a field enterable based only on another field's value
In FM11, I have a field to track the source of my contact. Multiple sources are possible, so I've set up that field on the layout to use checkboxes with a drop-down list, showing values from a "Sources" value list. One of the choices is "Recommended." An additional text field "Recommended By" is available for the user to enter a person's name.
1st scenario -- I do not want that text field enterable unless the Source field first has a checkmark selecting "Recommended."
Or, a 2nd scenario would be fine -- if a person DOES enter it and types in a person's name, then i would want to be sure that the "Recommended" choice is selected FOR them, if they haven't done it already. (I tried this route via an auto-entered calc on the Source field, but had to de-select the "Do not replace existing value..." for the Recommended choice to get selected, but unfortunately it also deleted (un-checked) any other Source choices that were already checked! maybe my calculation was just wrong, or maybe this isn't the route to use.)
Any suggestions for accomplishing either scenario?