I connected an external monitor to my Macbook Air, and arranged it above the MBA display. See this screen arrangement.
In the above screenshot, the up-display is the external display, and the down-display is the MBA display.
I want to use the MBA display for my main working display, and occasionally put some reference windows in the external display. So, I want the menubar stay in the MBA display.
The problem is that dragging a window from the MBA display to the external display does not move it. If a windows is somehow placed in the external display, I can drag it down to the MBA display.
How can I move a window from the MBA display to the external display?
I tried to arrange the displays physically up and down, but in the OS side by side. It is so confusing. So, I would opt out such an option.