[UNITY] Perspective Move Tool

public override void OnToolGUI(EditorWindow window) {
    Event e = Event.current;

    switch (e.type) {
        case EventType.KeyDown: {
                if (e.keyCode == KeyCode.LeftControl) {
                    adjustY = true;
                }
                break;
            }
        case EventType.KeyUp:
            if (e.keyCode == KeyCode.LeftControl) {
                adjustY = false;
            }
            break;
    }

    EditorGUI.BeginChangeCheck();

    Vector3 worldPos = Tools.handlePosition;
    Vector3 projectedPos = new Vector3(worldPos.x, worldPos.y + worldPos.z);
    Vector3 newPos = projectedPos;

    Handles.color = Handles.xAxisColor;
    newPos.x = Handles.Slider(projectedPos, Vector3.right).x;

    if (adjustY) {
        Handles.color = Handles.yAxisColor;
        newPos.y = Handles.Slider(projectedPos, Vector3.up).y;
    } else {
        Handles.color = Handles.zAxisColor;
        float y = Handles.Slider(projectedPos, Vector3.up).y;
        float delta = y - newPos.y;
        newPos.z += delta;
    }

    worldPos += newPos - projectedPos;

    if (EditorGUI.EndChangeCheck()) {
        Vector3 delta = worldPos - Tools.handlePosition;

        Undo.RecordObjects(Selection.transforms, "Perspective Move");

        foreach (var transform in Selection.transforms) {
            transform.position += delta;
        }
    }
}