Scale the whole segmentation

Can you clarify what you mean by this?
If you want to increase the resolution of your segmentation, you can use the segment geometry settings Oversampling option to do that. Putting in 2 as an oversampling factor will increase the memory usage 8 folds. So if you don’t have enough RAM on your computer you may encounter issues or sluggishness. See this thread

If this is not what you want to do, please explain more.