The position of the mouse in the scene

Godot Version

4.2.2

Question

The position of the mouse in the scene
I want to have 3 layers of canvas, but I put the “game scene” on one of the canvases, but I can’t control the “camera in the game scene”, but it is fixed in the “range and position of the window size”
So now I put it on “one layer below the root node”,
I want to click “Left mouse button twice” in “Game Scene” to put “Range 2D” to “Mouse Position in Game Scene”,
I spent 2 hours looking at the “official documentation” and only found “absolute position of the mouse in the window” and “event.position”.
I was in a hurry to finish and didn’t have time to find answers.
Why can’t I control the “size and position of the Panel” when I put “Game Scene” in “Panel”? I hope it’s only “on half of the screen”, but it’s actually in the full range.
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When I use “get_global_position ()” or “event.get_global_position ()”, both “the value is the same when the mouse is moved” and “the value is changed when the camera is moved”. Why?