Drag and Drop issue and Exposé

Question

I know that there are many people with the same problem and maybe creating a new topic might seem lazy but I've just found a way to replicate the problem in my system and that might enlighten somebody to find a way to fix it.
I've noticed that finder stops being able to "drag" a file in list view after I use Exposé to select the window. If I click out of the window into the desktop or some other window and click again without using Exposé, it seems to work just fine, then I Exposé out and back again, and no dragging.
This seems to happen every time I use Exposé to get to the window. I can use Exposé to get out of the finder window, and as long as I don't use it to get back to the finder window, dragging works.

Answer 1

to add to the last:
Henahn's observations are still exactly what is happening,
but the window size of firefox has nothing to do with it as I test it.
It is as Henahn's findings:
If I use the side buttons of the bluetooth mouse to activate Exposé and go to another screen where there is a open finder window with a selection; dragging that selection doesn't work.
Going back with Expose to the first screen, then mouse-clicking that desktop to activate the finder, then going back to the screen with the finder-selection will make the drag-function working again.
It is a work around, but what a hassle if you have to do this a lot.
Apple. Fix this please!