Transparency pick color dialog doesn't apear

[rundekugel]

1st: Thanks for IrfanView
2nd: I work with IrfanView since Win95. Saving ico with transparence worked
3nd: Now on a Windows10 machine I want a transparent PNG. Not the man window color. I don't get the dialog for picking the transparency color.
I tried also with "Use main window..." but python reported: "No transparency"
What can I do?

Windows 10 Pro, 19042.985
IrfanView 4.56-64

[Bhikkhu Pesala]

The first thing to try would be to upgrade to the latest version. I have no problem picking the colour using the same settings as in your dialog.

[rundekugel]

I had also issues with GIF.
Now installed Version 4.57:

Color pick dialog apears now.

Issue solved.