Not Able to Open Faceplate Sometimes

Recently I changed Passwords of Operator Account but after that I observed that sometime Operator not able to open any Faceplate even though he will click on Graphic Elements. Also tried by changing Grahic Display but I was able to change Graphic Display but not able to Open faceplate after Click on Graphic Element. When I close Operator Workplace and re-open it without Log Off, Situation became normal and was able to Open Faceplate. Earlier there is no such issue observed before change of Password. Please help to resolve it.. System 800xA 5.1 Rev C