Looking at this, here is what I see.
- If a channel has never had a font set, it will take up the font that is set as default automatically. To test, create 2 channels you've never been in. Change the font in one of them and set it as the default for channel windows. Both channels will change.
- If a channel has had a font set to it, then it will not change if you change the default font for channel windows. To make it change to the default font, you must go to it and select "use default font". To test, create a channel and set it to a specific font. Create 2 new channels that you haven't been to before and change the font in one to a different font and then set it to the default font for all channels. The two new channels will change, but the first channel will not. Go to the first channel and tell it to use the default font. It will then change. Now, go back to one of the new channels and select a different font and set it to the default font for all channels. All 3 channels will change now.
This seems like it's working the way it should. Which part are you experiencing the problem? Or is there some other scenario I haven't tested?