defect: mouse wheel behaves as if shift key is pressed

[xinhuaji]

My configuration: virtual box 1.50 host: WinXP professional sp2 guest: Fedora Core 7 with vbox additions installed

I noticed this unusual behavior when I was using firefox in guest OS. When I scroll up/down any webpage using mouse (middle) wheel, firefox will randomly jump to other page as if 'Forward' or 'Back' button were clicked. And this is very reproducible, especially when I quickly toggles between wheel up and wheel down (rub the wheel back and forth quickly).

Now as a fact Firefox actually supports mouse shortcut for 'back' and 'forward' action as 'shift+mouse wheel down' and 'shift+mouse wheel up'. So it appears to me that while I do not press any keyboard key, and am very sure that shift key is not accidentally locked, something makes Firefox thinks shift key is pressed at the time.

This phenomenon does not occur when vbox additions is not installed. AND, even if vbox does not capture keyboard, the problem still persists (I press right ctrl and the small icon in the right bottom corner of vbox window grayed indicating keyboard is not captured by guest OS). So I am pretty sure this is not a hardware keyboard problem. Also I do not have problem using firefox this way in host OS. So I come to create this ticket believing it is a defect of Virtual Box 1.50. I wanted to create a small movie recording this as proof, but can't find any handy software helpful so I gave up.