Chai, I read several times your OP, but it is so unclear…
You can indeed drag a canvas, and if the checkbox is child of that canvas, it will be dragged in the process. Since you mention a groupbox, I assume it is a Desktop project. It would be nice to post in macOS, Windows or Linux to make that more evident.
To make a canvas draggable, you need to store the click position relative to the canvas in MouseDown, then move the canvas, relative to the mouse position in mouseMove, if the mouse button is down.