Zoom with CTRL + Mouse wheel no longer working

Hi Everyone, 

On PP 24.0 I seem to have somehow changed the ability to zoom on a timeline using the shortcut CTRL + Mouse wheel.   My computer was unresponsive and glitching and while trying to recover I must have inadvertently typed some keys to change this setting?!

Now, when I try to do CTRL + Mouse wheel it seems as though the Audio/Video section under the mouse is attempting to scroll up or down. 

I had no idea how much this shortcut helped me move so quickly until it stopped working. 🙂 

Any ideas on how I can restore the functionality?

- Steve