Issue with Parametric modeling in Fusion 360

Issue encountered with Fusion:

I had already created a wheel housing for the 3rd version of the EnGen scooter when I created a linear gearbox to go inside. I created the gearbox in a separate Fusion file so that the part was clean and organized. When I inserted the gearbox into the wheel housing, I found it was too large for what I had previously designed.

This wasn’t supposed to be the end of the world – just make the housing larger and slip the gearbox in. But the size of the housing was determined by the very first sketch I made in this Fusion file.

Changing the height dimension from 50mm to 55mm suddenly broke a series of features in the timeline.

I had to roll back to the first error and start editing features and sketches until I was back where I started.