OS Version: 11.6
OS Language Setting: English
Application Shell: 3.0.9
If you have a Narrative View that uses a layout algorithm sufficient to make the data scrollable both horizontally and vertically, clicking on the vertical scroll bar and dragging down while letting the mouse stray a fraction to the right into the Inspector also drags the Narrative View to the right.
Likewise, if you click and hold the vertical scroll bar and move the mouse to the Panels on the left, it will scroll the view to the left.
Preferable behaviour would have the vertical scroll bar only affect the vertical scrolling, and the horizontal bar only affect horizontal scrolling, rather than a weird hybrid.
Create enough data in Narrative View to have data off the screen in both the horizontal and vertical.
Click and hold on the horizontal scroll bar.
Move the mouse into the Inspector (right) or Panel (left) and observe how this moves the Narrative view left or right.