You know you always answer with an aggressive tone ?
Anyway, you already explained clearly what you're doing with your fingers and what is happening
The video shows a little part of the mIRC's main window where we can see the grey background when your bug occurs and the fingers positions. We already knew we'll see -something like- this, same goes for the fingers positions.
So yes, the video is quite useless for me because it doesn't brings new information, but at least this post is useful :
1. The behaviour -only- occurs in mIRC (so I can't reproduce it by say, hovering my mouse near the right hand side of Firefox and doing the same thing).
3. The behaviour -only- occurs when the nicklist scrollbar isn't present (so it can't scroll).
The first one states it's only related to mIRC and the second one gave an information about how to reproduce the bug that is much much more important than the video
Again, it's not because I said that the video is useless that you have to say my post is too, or at least tell me why eh.
You didn't talk about the others programs, that's why I've asked you about why do you think it's a mirc's bug, and now we know.