I cleaned my Windows 7 machine by repartitioning it and such. After I installed Firefox 4.0.1 back, I noticed some significant change in its behavior.
The downloads dialog didn't list out the files. I googled and found the solution to this. The settings were in some obscure place and I wonder how I got it the last time around!
The downloads dialog no longer shows the size of the file, percentage downloaded etc under the progress bar.
The icon on the taskbar is no longer getting filled with a greenish tinge to indicate the progress of the downloads.
For the last two, I googled but didn't get anything.