I am using virtual box on ubuntu 14.04 LTS. I have tried with it Ubuntu 4.10, 5.04 and android x86. With all of them I have the same problem: After it says "Yor guet OS support mouse indergration", the mouse dissapears when it is on the guest OS on the screen, I can not even use it, and I can only use the guest OS from the keyboard. Neither the USB mouse, nor the mouse touchpad on my notebook work. How can I fix thiS? I saw a lot of questions with a similar problem, but I could not solve it.
I recommend turning off the automatic mouse integration, and instead using the keyboard-dependent capture mouse feature. With my computer, this involves using the right-control key to capture or escape the mouse and keyboard from the guest OS (it may be setup as something different for your installation). With this, you have more control over whether or not the computer thinks the mouse is in fact "in" the guest OS or not.