Hi,
Currently no, you cannot let the Magnifier visible when you leave its Target. Case 167323 has been created to allow this.
The solution would be to give a Freeze method to users, where an argument (true or false) would freeze or unfreeze the Magnifier. When frozen, no position updates of the Magnifier would happens (the magnifier would not follow the mouse). In addition, the Magnifier would not hide itself when users leave the Magnifier’s target element. It would go back to normal when a call to Freeze with “false” is called.
This way, users could use any combination (MouseLeftButtonDown, MouseLeave, Ctrl + C…) to freeze/unfreeze the Magnifier.
Could that be an option for you ? If yes, it would be available in v3.3.