I have been slowly working my way onto X7, and recently noticed this problem. I do a lot off map work and have a 2x2 setup of 4 monitors over which I could "stretch" my X6 Drawing window. It saves a lot of time by not having to scroll around as often when editing. I stretch a normal window to cover the 4 monitors, starting with the upper left corner down to the lower right. It works great. This also works in PhotoPaint, though I don't use it nearly as much.
Now that I have X7, I find that you can stretch a normal windows across 2 monitors (in fact, even 4 monitors) with no problem, BUT, you can only resize the window vertically to the extent of a single monitor.
This is clearly different from X6. Also, I find that if you use a desktop manager, you can aggregate individual monitors into a larger desktop, and in this environment you can resize Draw the full height of the virutal desktop.
I can use the nVidia Surround option, but that causes some other issues I would like to avoid.
i7-4930, 32gb ram. Dual GTX 760 video cards.
Suggestions welcome...
I found the solution without purchasing new monitors. I configured Nvidia Mosaic, for my video card, to cause windows to view all four monitors (2×2) as a single monitor. CorelDraw can span two vertical monitors or all four, if desired.