When saving with transparency the "Color Picker" does not appear

[Severh]

Hi there

I recently tried to create a transparent PNG file from an edited one.
First i had a non transparent PNG file. When saving and selecting output as PNG and selecting "Save Transparent Color" and de-selecting "Use main window color for transparency" i expected Irfanview will open the color picker to choose the color i want to use as transparent. It always did appear in previous versions. Unfortunately it did not appear ant the color i intended to pick was still there.
I attempted to save another PNG that had transparency (just opened and saved as) to see if in this case it will work but instead it lost its transparency information.

Is there any function in Iview that can disable the color picker?
Currently im using Irfanview 4.44 x64 with x64 plugins, on Win 10 x64. Also i use 2 monitors.
Any suggestion why this may be happening?

PS: I am certain that the area i want to set transparent is large enough to pick and is all in the same color (although the picture is 64x64 pixels)

[Bhikkhu Pesala]

The colour-picker won't appear if you enable "Use main window colour for transparency."

[Severh]

The colour-picker won't appear if you enable "Use main window colour for transparency."

I did de-select it.

and de-selecting "Use main window color for transparency"

Unless there is such option somewhere else than the "Save As/Save Options" window.