Since 4.0.0, I only get the advanced preview by default, where I can set the fee, view my inputs/outputs and click "Sign" or "Broadcast".
AFAIK, it's disabled by default on 4.0.0b0 till the latest, but it may be based from the OS.
You can clear the doubt by temporarily renaming the config file or "
electrum" folder in the appdata directory,
launch Electrum and it will open using the default settings, then see if advance preview in "
preference->transactions" is unchecked.
After the test, delete the new config file/electrum folder and rename back the original.