Opacity of object selected inside a group

[asturur]

When adding this test here:
https://github.com/fabricjs/fabric.js/pull/9735/files#diff-d3f16804ba71a176d9aacf645671c78bab4494635c3cc5ccf46bcc786bd7f8a0R326
You can notice the object is painted darker than the previous test.
This shouldn't happen since both rects have a 0.4 opacity.

This issue is to track investigation:
The code of test is either not sufficient to reflect a real selection, or in some way rendering is going wrong ( object painted twice ? )
It could be a case of preserveObjectStacking playing a difference or something else.
Find out and open an issue if it is a bug or fix the test right away.

[ShaMan123]

I have seen this in a ticket not a long time back.
Does it happen on node? Or did you use a browser for the visual test?

[ShaMan123]

For me this is good enough with the tests.
@ShaMan123 i notice a bug, the opacity of an object selected inside the group is not as i would expect it, is darker than the other case.
I do not understand why and i didn't test in the browser. i ll open an issue to investigate it

Originally posted by @asturur in #9735 (comment)

I see you didn't so perhaps I am right to point out node

Since node disables object caching try to set it and see what happens

[asturur]

I guess that the first one that has enough time can look at it.
If it was happening widely we would have heard about it.