2 questions: How would one delete  an execution group that is at top of a work sheet? Like this:

No matter what I do, I get a beep. I select it, click DELETE and nothing happens.

THe second question, is how to delete the last section arrow I added by mistake and do not want, this one:

I found I can remove if I select it with the line above, but then that would delete the code above also, which I'd like to keep.

Why is so awkward to use Maple user interface like this? Is this by design?

To make it easier, I attach the above notebook.

hard_to_delete.mw

I prefer to write packge:-command(....) so I can see which package the command is from.

But sometimes I am forced to load  a package. Here is an example. IntegrationTools contains some useful types

At load time the IntegrationTools package defines three new types: Integral, DefiniteIntegral and IndefiniteIntegral, which can be used to access integrals involved in any given expression.

I thought I can access these just like the commands in the package, using ":-" notation, but this does not work

------------------
restart;
v := Int(sin(x), x);
type(v,IntegrationTools:-IndefiniteIntegral);
---------------------

Error, IndefiniteIntegral is not a command in the IntegrationTools package

But this works

-----------------------
restart;
with(IntegrationTools);
v := Int(sin(x), x);
type(v,IndefiniteIntegral);
----------------

It looks like :- only works to access functions/commands/procs in a package. and not to access types such as in this example.

Is there some other notation to use to reference types in package without having to load the whole package?

according to help on Combine

The Combine command combines integrals using linearity. The parameter v is any expression involving definite or indefinite integrals.

So, why I get an error from the following?

restart;
expr:=Int(sin(x),x) + Int(cos(x),x);

IntegrationTools:-Combine(expr);

Error, (in IntegrationTools:-Combine) invalid subscript selector

interface(version);
 Standard Worksheet Interface, Maple 18.02, Windows 7, October  20 2014

I am trying to learn the <> notation to enter matrices and vectors. But I find this page very confusing

http://www.maplesoft.com/support/help/maple/view.aspx?path=examples%2FLA_Syntax_Shortcuts

it says:

but we see clearly the vertical bars are used to separate columns.

Isn't a column the thing that goes from the top to bottom and not from left to right in Maple LinearAlgebra?

Sorry for basic question, Maple newbie here and I could not find answer using google.

I understand in Maple one uses the back quote key (or rather the apostrophe, 0X27) to prevent one time evaluation of expression. Hence when writing

'sin(Pi)'; #this remain sin(Pi)
%; # now we get 0

But when I tried it on fraction, it did not hold it:

'16/4'; #maple replied with 4

This might indicate that the front end parser did this simplification before the main evaluator got hold of it, so it was too late?

Either way, how would one make Maple return 16/4 when the input is '16/4'?