Like most programs lines of code need to be inserted or deleted as the program developes. I have not found a way to insert a line of code between two lines. Nor delete an unwanted line. Is there a key combination that can do these? Growing and shrinking at the end is well described but in the middle of the subroutine I haven't found anything yet.

Hello,

You are right. I also think there is no way to insert or delete the expressions between two lines in the "line" environment. The only way is to expand it and have the extra empty lines. Then, editing the code is by using cut/copy/paste. After finishing, the extra shrinking is needed. I might be wrong, of course. This is higly desirable option, ecpecially when SMath will have a multiline function which will return a value or expression defined by using line environment (I hope in the very next releases).

Regards,
Radovan