In the latest update to Adobe Reader, the title bar has been merged with the tab bar. This means that when I have x number of documents open, filling the tab/title bar with tabs, it becomes very difficult to move the whole app window using the drag-and-drop with the mouse, since there is basically no area to click to grab the app window. Instead, you end up dragging one of the tabs out of the main window to open it in a new separate main window.

Being able to grab the title bar for moving the window is an essential windows feature, do not mess this up trying to cram all the menus etc. into as little space as possible.