Add null check for disposal safety
Add null check for disposal safety

NeoAdonis/osu,peppy/osu-new,UselessToucan/osu,smoogipoo/osu,ppy/osu,peppy/osu,smoogipoo/osu,UselessToucan/osu,peppy/osu,NeoAdonis/osu,NeoAdonis/osu,smoogipoo/osu,peppy/osu,UselessToucan/osu,ppy/osu,ppy/osu,smoogipooo/osu