It is a really good as well as annoying app. It opens all office files perfectly, but when i am unaware that my excel file has multiple sheets, i miss all sheets except first, which a viewer is expected to show(i know there's parts option in 3 dot menu & also swipe gesture for parts doesnt work with android gesture navigation). Please kindly move your parts preview bar to bottom with permanent visibility (instead of 'swipe to show' on side)or just change app's name to 'Libreoffice (DIY) viewer'.