Possible Clues:

• Volatile artist's technique occupying the mind
• Met up for a final word on chess champ that's moody
• Sid's paint choice showed capricious thinking.
• Having a volatile disposition
• Volatile paint meant finding replacement line
• Paint bats being moody
• Likely to act unpredictably
• Subject to sharply varying moods
• Office worker taking long time — intellectual and volatile
• Moody doctor met male parent