Closes #3098.
# Conflicts: # osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs # osu.Game.Rulesets.Mania/UI/ManiaRulesetContainer.cs
# Conflicts: # osu.Game/Rulesets/Edit/HitObjectComposer.cs # osu.Game/Screens/Edit/Screens/Compose/Layers/HitObjectMaskLayer.cs