running user app instance has a black icon, and other instance experiences.

I am running Qt 5.15.0 in a chrome Os
Version 85.0.4183.39 (Official Build) beta (64-bit)
which is running a Debian Buster linx system
in the penguin container (up to day).

I have 7 projects (outside of the examples) and 3 examples.
In the "files" application there is a folder named "images". it contains
a read only collection of images that it can find on the system.

I have my Chrome OS and linux files shared. (mainly because
I want to access the chrome os files in linux.

in the "Images" folder there are 7 icons, all copies of the Qt Creator
icon. When I click on one of the icons and select "go to the folder"
I receive a message that the Icon is in a shared linux folder.

When I run a Qt project (build and run), an entry is added to the
launch shelf for that running application. In the past it showed
the default "linux icon". But lately it is not showing any icon, but
a black position where the icon is. I can click on that area and
the application window wil; be displayed.

If I have multiple instances of the application running, because I
forget to close the previous test, each instance has an output
window open. When I right click on the "black" icon, each instance
of "hello word" is listed. Now just trying it again, it only displays
one "close option", which seems to cancel all of the running
instances. But I made changes in the past and now all I did
was press the build icon multiple times.. When I select that
one "close" option all of the instances are terminated.

When I have multiple instances running and a close the Qt Creator,
I am prompted to close each individual instance.

I don't know why sometimes right click show multiple instances
and other times it does not. When given a single option of close
all of the instances go away but the output windows do not
close.

i realize this is all new for you. The same as it is for me.
The Icon situation and the handling of multiple instances
running at the same time needs to be addressed. You may
want to consider asking if the user wants to close the previous
instance before running the next build. And then make it an
option to always do that if the user wants to not be bothered
by the question.