When you first start the installer, it seems the focus is on the preset dropdown.
Twice now I have started scrolling down with mouse wheel (thinking I'd scroll down the whole window) and end up switching between presets - obliterating my carefully selected settings. I end up having to redo all my settings, which takes a while.
This is very annoying, and I think at minimum the focus shouldn't be on the dropdown in the beginning. Preferrably selecting presets should be made more difficult - maybe open a new window where you can select preset, click on that and the installer asks if you really want to remove your previous settings.
Just my two cents.