@Carl Love 

Thanks, that is exactly what I needed.

@Christopher222

Thanks, Christopher. 

(In Document Mode)

I know I can assign with := but if I write 

A=0

and right-click on this expression there is an option Assign Name in the context menu. However, if I type

A=(1,2,3)

an right-click on this expression a much shorter context menu appears. It contains only the items Cut, Copy, Copy Special, Paste, Executable Math, Evaluate and Display Inline, Explore, 2-D Math and Create Task. Some of these items are greyed out.

I wanted to understand why the context menus are so different in the two cases.

@Carl Love 

Terrific! That is what I was looking for.

Thanks, Carl. That was useful information. But I am afraid not enough.  For example, I defined a function and tried to get more info about it using the commands you suggested:

restart:
r:=x->x^2;
whattype(r);
about(r);
indets(r, anything);
ToInert(r);
dismantle(r);

Of all these commands the only one useful (to me) was ToInert, which returned

_Inert_ASSIGNEDNAME("r", "PROC")

That probably means r is a function. Given that, I would like to find out what are its arguments and their types, its body, what type of object it returns, etc. Is this possible?

Thanks again.

@acer 

I removed all other commands and it worked!

Is there a way to "accept" your answer (as done in StackOverflow)?

Many thanks.

Thanks acer.

I copied the maple.ini file to the folder whose name is returned by the command 

kernelopts(homedir);

My commands 

    with(plots);
    setcolors("Spring");

were in the first two lines of the maple.ini file. When I restarted maple I got the following message:

Error, on line 4, syntax error, missing operator or `;`:
Open Hyperlink Location=101
^
Error, while reading ``C:\Users\Fernando\maple.ini``

So Maple is reading maple.ini. I tried then to move the two lines above to the end of the file. I no longer get an error message when I restart Maple but also the palette remains at its default value.

I noticed that there are no true Maple commands in maple.ini. What is written on each line never ends with a colon or semicolon. Should maple.ini contain a section where Maple commands should be placed?

Thanks again.