Leaving the futon out with 〜っぱなし
Grammar Explanation: Leaving something as-is with 〜っぱなし

Yotsuba invites her neighbors over for coffee. She first gives the three a tour of the house, leading up to the kitchen.
- 風香:
- 「洗
( い物( がたまってるのが気( になる…」- “It bothers me that these dishes are piled up...”
- あさぎ:
- 「私
( は廊下( のスミにホコリがたまってるのが気( になる」- “What bothers me is the dust built up in the hallway.”
- 恵那
( : - 「おふとんだしっぱなしが気
( になる」- “It bothers me that the futon is left laying out.”
Key Points
出
( しっぱなし means left outだしっぱなし describes the futon being taken out and then left that way.
The concern is the lingering messy state, not who put it there.
Each speaker uses 気になる for what bothers them
気
( になる repeats across the scene as each visitor notices a different mess.
The noun phrase works as the subject
おふとんだしっぱなしが気
( になる treats “the futon being left out” as what bothers her.