SQL Prompt does take some practice to get used to it being involved with your TSQL. I've gotten rather good at hitting the 'Esc' key when I know it's just getting in my way.
Maybe more functionality will be included in the final release.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning