I am not sure if this is a setting / UI issue in Firefox for Android or if it is a UI thing for Android in general.

I am using an Acer tablet with Firefox for Android. Before, I would use the three vertical dots icon to get the menu to display on the right of the screen (for example, when I need to search for text or look through the browser history). Now it is suddenly appearing in the middle of the screen instead and I can't work out how to put it back. I tried dragging it to the side, and double tapping on it, and looking through the settings. I searched online, but all I got was stuff about moving the address bar to the top/bottom or tips on menu design.