Although it's probably a glitch in Yahoo IM, it's possible the keyboard is on the fritz.. Swapping in a known "good" keyboard might solve the problem.
Hope this helps.
You may not beable to help me with this,as it maybe a glitch in Yahoo Messenger prog. When using yahoo and typing in an open dialog box,and hit the ''shift key'' the dialog box is closed,and minimized.Have used this IM prog. for sometime,and this little snag just started happening.I rebooted,but did not solve it.OS W98SE IE6SP1
p.s.this only happens when using yahoo msg.