Hi, this can be influenced by a particularly long bookmark, but also, the location of the bookmarks button can change the way it opens. For example, I have moved the bookmarks button to the left-hand end of the bookmarks bar, so everything opens to the right, simply because there is no space on the left. It's possible therefore, that another button you've added has moved the it to the left - leaving more space on the right. So you could perhaps try dragging it to the right - click on Customize as shown in [[Customize Firefox controls, buttons and toolbars]] and you will be able to move it. Alternatively, you could just add a long bookmark! ''If your question is resolved by this or another answer, please take a minute to let us know. Thank you.''