Description of the Issue

With the recent addition of Dark Mode to Npp and also recent commits in last day or so adding Dark Mode support to Function List pane has made it clear that there are some missing Fluent UI icons there.

I noticed that the Function List utilizes the older style BMP icons which uses the corner pixel trick to achieve transparency. I have tried multiple attempts to create some Fluent UI icons for Function List over the past few days with no success.

Here are my most recent failed attempts:

Something seems to be going wrong with that whole corner pixel transparency trick causing this and I have tried a bunch of different icons with no success.

• Would it be possible to somehow program the Function List so that it utilizes the already existing ICO format Fluent UI set?

I believe the only icon missing from the set that we would need is a Reload icon in the Function List. I can add the icon once the coding is in place to allow ICO.