Impossible to edit combo colors of skins based on builtin skins

[quat1024]

Type

Game behaviour

Bug description

If you make a skin based off of a builtin skin (like Argon or osu!2013), export it, and try to edit the combo colors in skin.ini, they will be silently ignored in favor of the game's default combo colors.

I have a long reproduction video in case it helps. Here's what I do in the video

1. Select a skin like osu!2013
2. I play a map with "beatmap colors" unchecked just to show the default combo colors in use
3. Open the skin editor and create a customized copy of the skin
   • this isn't an unusual use case, e.g. if you open a default skin and customize the hit error bar or leaderboard position, you'll be on one of these skins. in the video i just hit Save though
4. Select "Edit externally" and change the combo colors in skin.ini. I set them all to 255,255,0.
5. Play a map with "beatmap colors" unchecked. The game still uses the default combo colors (green, blue, red, yellow)

To show it's not related to any misimports from the "edit externally" button (e.g. #33989)

1. Export the skin
2. Delete the skin
3. Close the game
4. Extract the osk and change the combo colors in skin.ini (i set two of them to white)
5. Rezip the skin and import it into the game
6. Play a map with "beatmap colors" unchecked. The game still uses the default combo colors (green, blue, red, yellow)

To show it's related to the skin instantiation info:

1. Delete the skin again
2. Open skininfo.json from a donor skin (I imported some random osu!stable skin into osu!lazer and then exported it)
3. Copy its InstantiationInfo into the skin
4. Rezip the skin and import it into the game
5. Play a map with "beatmap colors" unchecked. Now the yellow/white custom colors from skin.ini are being used.

Screenshots or videos

https://youtu.be/PG1SxSv0PIM

Version

2026.724.0-tachyon

Logs

compressed-logs.zip

[bdach]

osu/osu.Game/Skinning/DefaultLegacySkin.cs

Line 46 in 0f3d3c3

Configuration.CustomComboColours = DEFAULT_COMBO_COLOURS;

osu/osu.Game/Skinning/ArgonSkin.cs

Lines 51 to 71 in 0f3d3c3

	Configuration.CustomComboColours = new List<Color4>
	{
	// Standard combo progression order is green - blue - red - yellow.
	// But for whatever reason, this starts from index 1, not 0.
	//
	// We've added two new combo colours in argon, so to ensure the initial rotation matches,
	// this same progression is in slots 1 - 4.
	// Orange
	new Color4(241, 116, 0, 255),
	// Green
	new Color4(0, 241, 53, 255),
	// Blue
	new Color4(0, 82, 241, 255),
	// Red
	new Color4(241, 0, 0, 255),
	// Yellow
	new Color4(232, 235, 0, 255),
	// Purple
	new Color4(92, 0, 241, 255),
	};

I'm not entirely sure whether this was the intention and history does not help to answer that question, but it definitely looks like the default legacy skin and the argon skin will overwrite any user-specified colours.