For those who are transitioning from a Windows-based computer to a Mac, resizing a window can get particularly tricky. I remember getting frustrated when I first started using OS X.
If you are familiar with previous versions of OS X such as Leopard and Snow Leopard, you know that there is only one corner that will allow you to resize a window. You could resize said windows by clicking on the lower right corner of the windows, made noticeable with a couple of diagonal lines – the resize handles – , and then dragging it to your desired size.
With Lion, there are no more resize handles on the lower right corner. Instead you can now resize your window from any corner. Just hover your cursor over your chosen edge and wait until said cursor changes into a double-headed arrow. Once the arrow appears, you can proceed to drag the window until you reach your desired size. You can drag diagonally to include both the vertical and the horizontal resize.
Some applications are not fully aware of the changes in the resize windows. So you might still see some applications having the resize handles on the lower right corner of their windows. Not to worry. Even if they have resize handles, you can still adjust the size of the window from any corner.
This way resizing windows is really easy!