How do I get Expressions to stay in their places in the score? Is there a command?

Not enough info.

Normally expressions do not move by themselves.

a) What are you trying to achieve?

b) How are you trying to do it?

c) What happens when you do that?

d) What doesn't happen that you expect to happen?

Many thanks, Peter! Well, here it is: "rall.", "rit.", "ten.", etc., refuse to stay in the instrument lines, whereas "ff", "mf", "mp", etc. ALWAYS stay where they are placed. 

… "rall.", "rit.", etc., refuse to stay in the instrument lines, whereas "ff", "mf", "mp", etc. ALWAYS stay where they are placed …

You are using Finale v27 - right?

I suspect that it is matter of Expression Tool settings.

In the Expression Tool the expressions are organized in expression categories.

In the dialog box Expression Selection you can move expressions to another category.

Document menu > Category Designer…

In the Category Designer you can edit the expression categories.

Each category has its own settings (which you can edit).

Change a category’s settings, to change the settings for all the category’s expressions “at one fell swoop”.

You can create a new category by duplicating an existing category. Then, edit the duplicate.

Expressions such as "ff", "mf", "mp", &c. normally belong to the expression category Dynamics.

It seems that the Dynamics category has the settings you need.

Expressions such as ""rall.", "rit.", &c. normally belong to the expression category Tempo Alterations.

Take a good look at the settings in the Tempo Alterations category.

You may find something wrong in the settings.

Per your suggestion, here is the result: Expressions > Tempo Alterations > Select Alteration (e.g., ten., dim., rall., etc.) > Move To… > Select Dynamics, immediately gives me the result. Thanks very much, Peter! -Ed

Dear Peter, 

I am using Finale 27.4. 

 I had a massive stroke 5 years back, which makes it hard for me use the left cranial lobe. Difficult! I make lots of mistakes.

Once upon a time, I used the used "A" to add "a tempo," in order to get the music to resume its standard velocity. But now,  I can't use "a tempo" --at least in this music-- to resume its speed, after "ritardando" ("rit.").

Any additional thoughts?

Ed 

If I understand you correctly, this issue is a matter of playback - right? (not a matter of layout)

Are you using Human Playback in the Finale document that gives you trouble?

Yes, Peter. I am using "Standard" in Human Playback. Should I be using another?

Unfortunately I am unable to reproduce your problem.

For me, Human Playback interprets the tempo alterations.

What I did:

a) Enter a Tempo Mark at the beginning (= defining the “standard tempo”),

b) Add “rit.” to a later measure,

c) Add “a tempo” to a later measure.

When I click the Playback button, the playback begins with the tempo mark’s tempo, slows down at the “rit.”, and resumes the initial tempo at the “a tempo”.

Thanks, Peter.

"For me, Human Playback interprets the tempo alterations." That was always the case for me. 

But I found out yesterday how to hide an expression tool (i.e., mm.= 76), so that the playback plays the "a tempo" after the "rit." I have no idea why the "a tempo" no longer works for me in "Classical" or "Standard" Human Playback.