Comment 141 for bug 39315

I've had this problem for several years and have finally found a workaround that works for me.

My current system is:

Xubuntu 16.04 LTS
Advent wireless mouse (also happens with other mice, including wired)
SynPS/2 Synaptics TouchPad. Disabled in "Mouse and Touchpad" application.

The reason I use a mouse is that I don't get on with touchpads as I tend to catch them when typing, and even if I set the "Disable while typing" option, I find that I sometimes still accidentally move focus out of where I'm typing (really annoying).

I suspected that the touchpad was causing the problem, even though it is "disabled".
I have now covered the touchpad with a piece of cardboard, loosely taped into place.

When the touchpad is covered with card, no problem.
When the touchpad is not covered with card, I get the problem.
Cover with card again, no problem.

I suspect what is happening is that messages from the touchpad, when I accidentally catch it with a thumb while two finger typing, is somehow interfering with messages from the keyboard. If the key down event is lost or delayed, a typed key fails to register. If a key up event is lost or delayed, the key repeats.

I have tried most of the suggested fixes in this thread and elsewhere, but so far the only solution that works for me is to physically cover the touchpad so that it is mechanically disabled.