Ok I have done some experimenting. I agree this is a rather unique recording mode which seems to be a Sonar thing. And it may not be exactly replicated in Studio One (yet!) I will keep testing though.
Here is a work around. You need to do three things.
1 Create a keyboard command for the duplicate track command. (not duplicate complete!, just duplicate track) There is not one right now so you will have find a qwerty key that is not being used or use a modifier for one that is being used but I suggest find a spare key letter. 2 Go to Studio One Preferences (on Mac) or Options (PC) and go to Advanced/Console. Now check the box that says Audio Input follows selection. 3 While in Preferences or Options/Advanced/Console check the box that also says Audio Track monitoring follows record. (that is if you are feeding a signal into Studio One and you are monitoring it via the software monitoring mode) If you are monitoring through an external mixer then you don't have to do this.
Now this setup does create separate tracks for your takes as you piece the solo together for example but the good news is this is seriously fast.
Setup an audio track and record the first part of your solo. Stop at some point.
Press you new keyboard command you have made and you will instantly get a new track. The previous track will jump out of record and the new one will be set to record (and software monitor)
Just hit play and you will hear first part of your solo, hit the * button on the numeric keypad and you will be instantly in record for the newly created track so you can complete second part of solo etc.
Note you can also set the loop start point where ever you want and get Studio One to jump into record there for you. If you have got any of the Faderports, you can connect a foot switch and get this to go into record too. Keep going as needed. You will hear every track play back. Keep adding on and extending the solo say on the last newly created track. You can replace any section too. Just stay on the last track and don't press the duplicate track key command until you are ready to move on. You can also jump back to any of the previous recorded tracks and re do bits as well. Any track you select will be in record.
The advantage of all this is you will see all your takes on sep tracks. Then just cut and paste and move all the bits onto a single track. Do fades as needed to smooth transitions. Do a CtrL B on the whole thing to get a new bounced audio of the whole thing.
Not perfect but also not bad either and quick too. You will get fast at doing this.