Like others I was forced to upgrade from v1.8, which worked very well with no issues, to v1.9. I have 5 computers and have a problem with v1.9 on 2 of the 5 computers.

While playing WoW, the 2 computers in question have a tendency to tab to Windows. This appears to be related to hitting the tab key in quick succession, as I do for example in PvP. Obviously this is very serious in PvP and is not an issue I had with v1.8. As there have been no other changes, I assume this is a v1.9 issue.

The 2 computers have Windows Vista.

Any suggestions as to how to resolve this issue?