I've recently updated to Opera 45.0.2552.898.
Now the side bar cannot be hidden anymore. It is always visible on the start page.
When another page is open, it disappears. But the hide button is gone. There is only a freeze option now.
Have I missed a now hidden option?
Also: I was trying to get back the former menu bar on top. In previous versions one could chose to hide the dropdown menu and instead get a bar on top of the window that contained bookmarks and also the menu.
And thirdly: previously one could enable the deleting of the history on shutdown of the browser.
Where is this handy function gone?