Reported Show channel in PNG file with Alpha channel - bug or feature?

[bflmpsvz]

At first, there is mistake in the IrfanView Help - version 4.44 . It says in section "Show channel":
"Note: see Properties->Browsing/Editing if you want to show a channel as color or grayscale. "
But this option was moved to section Properties->Viewing . The help should be changed accordingly.

When I want to see channels in .png file containing Alpha channel, IV shows Alpha channel from the file, but R,G,B channels from result which is seen in IV window, and this result depends on the "Main window color". I do not know what this result could be good for, but I need to see real color channels. If the Alpha channel is read from the file, why not Red, Green, Blue channels?

Let's have this image, png with alpha:

Let's have this setting:
Checked:
Options->Properties->Viewing Show PNG/TIF/TGA/DDS alpha/transparent color
Unchecked:
Options->Properties->Viewing Show channels in color (for menu: Image->Show channel)
Set:
Options->Properties->Viewing Main window color (75, 75, 75)
Now, how channels really look like and what IV shows:
Real Red: IV shows:

Real Green: IV shows:

Real Blue: IV shows:

Real Alpha: IV shows (O.K.)