No, there is no built-in setting for such a timeout. You could use a batch file which auto-exits HeidiSQL after a specific time, but that's not necessarily inactive time:
start "c:\program files\HeidiSQL\heidisql.exe"
timeout /t 60
taskkill /im heidisql.exe /f
Oh wait. I think at least for MySQL/MariaDB, we almost have it without external tools:
- disable automatic pings in your HeidiSQL session, on the Advanced tab (set to "0")
- activate "Prompt for credentials"
- let the server disconnect the sessions after whatever the
interactive_timeout variable is set to (default is 28800s = 8h, you can change that in the servers my.ini file)
Now, after 8h of connection inactivity, HeidiSQL reconnects you automatically. This is even automatic when you have the "Prompt for credentials" active. I would change this behaviour for future builds if you say that would be useful?