Multiple resources allocated when only one was selected

[Kent2102]

Hi, I'm having an issue with resource allocation in Project'07, when opening the Assign Resource screen the resources all start by being selected, clicking on one resource and then the Assign button causes all resources to become allocated. If I then click Undo the problem is instantly fixed and the correct resource is assigned, or if I press Enter instead of clicking the button it works as it should.



Does anyone have any ideas as this problem doesn't seen to occur on every computer?