Problem: A DOS program running in DOSBox used the mouse, and now you can no longer get the mouse of the DOSBox.

Solution: Press CTRL+F10

If that does not work, press the Windows key on your keyboard.

Problem: After using the keyboard (by typing) or after changing the volume using a button on your laptop, the track mouse becomes unavailable for a few seconds.Problem is present on Ubuntu 11.04 (or Linux using a Synaptics touchpad mouse driver).
This problem is likely present on other distributions.

Cause: Ubuntu 11.04 changed some of your mouse settings, upon doing so it enabled a feature titled “Disable Touchpad While Typing”

Solution:
(Ease: Easy. Time: Under a minute)
This solution will likely work on other distributions, but the menus may be in different locations.

Enter your system settings
* Gnome3/Unity: Press the Windows Key and type “Mouse”, select “Mouse and Touchpad”
* Gnome2/Failback: Click your username in the upper right-hand corner, and go to “System Settings” and locate “Mouse and Touchpad”

Go to the “Touchpad” tab.

Uncheck the box next to “Disable Touchpad While Typing”

Close the window, and test that it resolved the issue.

Did this work for you? Please comment and let everyone know.

More information about this is available here:
https://help.ubuntu.com/community/SynatestingpticsTouchpad