No NOT at ALL.
If you always leave the AC power connected the battery will charge to 100% and then stop. Leaving it connected to AC the battery will drain slowly until it get to around 92% and then it will start the recharging again. This is to stop what is called Short Cycle charging where if you disconnect the AC and you only use it until the battery gets to 95% and then reconnect the AC it will NOT charge. The battery has to be below that 92+/-% before the charging circuit starts charging the battery again.
So you can most of the time leave it connected to the AC and it will work the battery. But it is suggested to run it on battery only every now and then.
Basic rule. Use it on AC unless you can't or it is to inconvenient to connect it to AC and you will not run the battery down below 20%. Once you get to around 20% Always Reconnect it to AC.