When coding, you often have to mark variable names, field names or function names to exchange these and only these. I often try to ease this by double clicking, expecting to mark a field name, a function name or a variable name completely.
But this doesn´t happen. If a field name consists of two words, I only get one word marked, if a fieldname is followed by =, than this and more is also marked. If you have something like "&field1&field2&field3&" and doubleclick on field2, you get the whole text marked and not only field 2. This is very annoyable, since you can only manually mark the part of your formula you wish to mark.
A big boost would be, if Filemaker marks only complete field names, function names and variable names in the formula editor, when you doubleclick.
Consider this as a bug or feature request, I don´t mind.