Storyline 360: Slides are aligned horizontally

Hi, I have been using SL to simulate a software workflow, so a recorded screen was inserted in step-to-step mode. Each individual slide works great, when I click the correct hotspot, it takes me to the next slide. However, I no longer have that nice vertically aligned thumbnails in the left window. 

I understand it does not impact how the slides will behave and it's all controlled by triggers, but it's painful for the instructor (me) to navigate around, as I cannot simply scroll. I have just started a scene with 60 slides, it's not fun... 

Since it's a recorded screen divided into many slides by SL, I definitely don't want to mess up the triggers or reconfigure them one by one. Is there a way to "fake in" the vertical alignment just for a better navigation?