Mouse clicks move mouse pointer, and mouse not properly captured

[Andreas M. Kirchwitz]

Running VirtualBox 4.0.8 (32 bit) on Fedora 14 (32 bit) with guest Windows XP SP3 (32 bit, 1024x768). The host has a single display (1280x1024), PS/2 mouse, window manager is fvwm2. Everything was fine about 3 months ago (IIRC that was with VBox 4.0.4).

Started Windows XP today, and as soon as I hit the left mouse button for the first time, the mouse goes nuts. On each click, the mouse pointer is relocated on the screen (makes double-clicks impossible). Mouse movements do not properly end on the edge of the screen but just in the middle of the movement the guest mouse pointer is relocated and mouse control is back under Linux control (a little bit like the Host Key has been pressed during the movement; changing it doesn't help).

Guest additions are not installed (so there's no special mouse integration). It's a standard setup.

I've also moved the old installation out of the way, removed the VirtualBox package, reinstalled it and made a Windows XP (SP2) install from scratch. Same behaviour.

It doesn't look like this is Windows' fault, because it happens with a clean Windows XP SP2 as well as a fully patched and customized Windows XP SP3. Looks like VirtualBox and Linux (Fedora) no longer work well with each other. Fedora is fully patched.

I've also tried a USB mouse (just in case VirtualBox has problems with PS/2), but that didn't change anything. It doesn't look like a hardware fault because everything is recognized and basically works.

Same problem with different screen resolutions within the guest system.

I'm wondering that simple mouse movement can cause the mouse to be no longer captered by the guest system. That should be impossible without the Guest Additions.

I'll append a VBox.log but there are not errors in it.

[Andreas M. Kirchwitz]

I was able to nail down the problem a little bit more:

If I click (left mouse button) in the VirtualBox window with the running guest (Win XP) to make it capture my keyboard and mouse events, VirtualBox fails to read mouse events properly and goes nuts.

If I do not click with the mouse but use the Host Key instead, all is well and works as expected.

With Guest Additions installed, the Host Key is basically useless, so VirtualBox behaves like if I click in the window (and goes nuts). Thus, with Guest Additions installed (or to be more precise: active), VirtualBox 4.0.8 is not usable on my Fedora 14 right now.

Disabling Guest Additions and always using the Host Key is a workaround (but doesn't solve the problem).