bookmarked items appear in history column
Each time instead of getting a new tab or replacing the existing tab any bookmarked item appears where the History column appears on the left side of the displayed tab. It used to replace the main tab window but now acts strangely.
Alla svar (1)
Opening in the sidebar is the default for bookmarks that are created via a link or button on a website. You can check the properties of a bookmark via the right-click context menu in the sidebar (Ctrl+B; Command+B on Mac). In the Bookmarks Manager (Bookmarks > Show All Bookmarks) you can click the More button in the Details pane at the bottom right. Make sure that "Load this bookmark in the sidebar" is not selected.