diff --git a/osu.Game/Overlays/Mods/ModPresetPanel.cs b/osu.Game/Overlays/Mods/ModPresetPanel.cs
index 450c684e54..568ca5ecc9 100644
--- a/osu.Game/Overlays/Mods/ModPresetPanel.cs
+++ b/osu.Game/Overlays/Mods/ModPresetPanel.cs
@@ -55,6 +55,9 @@ protected override void LoadComplete()
 
         protected override void Select()
         {
+            // this implicitly presumes that if a system mod declares incompatibility with a non-system mod,
+            // the non-system mod should take precedence.
+            // if this assumption is ever broken, this should be reconsidered.
             var selectedSystemMods = selectedMods.Value.Where(mod => mod.Type == ModType.System &&
                                                                      !mod.IncompatibleMods.Any(t => Preset.Value.Mods.Any(t.IsInstanceOfType)));