When I have a PDF document opened in Acrobat, if I resize (or maximize) the window, the document inside stays the same, i.e., I'm not viewing any more of the document. Only some blank space is added around the document. The scroll bars stay with the document too. Please see the attached screenshot to help you under what I mean (note the gray blank space between the scroll bar and window border).
Same behavior if the PDF is opened in a browser window.
Is this behavior by design or is it a bug/setting issue? It's very annoying. I can work around it by forcing it into full screen view, then back, then the document will fill the whole window. But it'd be nice to fix it.