I think you are confused, at least I think I am. (You should supply code that shows us 1026324980834960100)
How did you get that value? Did you just directly std::cout << the floatrect? width/height are not coordinates, but top and left are. You can thus get the other corners by decrementing top by height, incrementing left by width and doing both for the bottom right corner.
I then use this to find out whether the mouse is within that box area, in order to drag and drop. The actual program works fine. What I would like to do is cut these 4 lines down into a single one, if possible. I am fairly new to this so I hope you will bear with me.