Description of problem:
The "Details" section of the Software Update window is too small. It fits maybe 2-2.5 lines of text, which is barely enough to read the name of the application and maybe the date.

Version-Release number of selected component (if applicable):
gnome-packagekit-3.4.2-1.fc17.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Open Software Update when there are updates available
2. Select an update
3. Click the + to open the Details
  
Actual results:
Details section is very small, no matter how large your screen is (see attached screenshot).

Expected results:
Details section should show a useful number of lines. How large that would be is a bit difficult to say. On the given screenshot, maybe about a 1/3 of the height, but on smaller screens, perhaps less.