Windows 7 & Excel, docking bug

So the other day I was using Excel for some work I needed to do. Maximized the window with the mouse, very nice feature in 7. Ups, wrong minotor I docked the window on. So I wanted to move it to the other monitor. But wait, I could not undock it when trying to undock it from maximized with the mouse. So clearly a bug ... wheater its in Wind ows 7 or Office that causes the window to not be undockable from maximized I dont know ... 

Its no problem when its docked to either left or right ... but, not impossible to undock from maximized with the mouse ...

So if anyone know I can report this, please do tell.