Sidebar on my iPad won’t close.

Hi, the sidebar on my iPad won’t close. It doesn’t matter whether I touch the history icon, the reading list icon, or the book icon… Nothing closes it. I have tried double tapping those icons, I have tried swiping the pain to the left or the right with its border, and that doesn’t work either. I have even close the multitasking option in settings. Please advise. Thank you in advance!