@leocg I created account on opera only for this comment. Don't take me wrong but every browser is allowing user to modify some basic functionality. While vb666 used bad language it DOES NOT make the issue less relevant. The sole fact that you are not allowing users to change the most basic thing in the browser is really unacceptable. What amazes that 5 (or 6 depending on country) built-in search engines but you are not allowing to remove, you are allowing users to add their own search engines but you are not allowing them to change them to use them as a default.
vb666 should probably watch his language but you should watch your customers unless you have very good and reliable source of financing your project.
By the way - I am using Opera only to download other browser because Opera pages are the only reliable pages working evn in outdated IE however I have no problems to switch to Vivaldi.