OnLoad of project task form throws an error : client script error:"onChange script error: TypeError: PmClientDateAndDurationHandler is not a constructor"DescriptionOnLoad of project task form throws an error : client script error:"onChange script error: TypeError: PmClientDateAndDurationHandler is not a constructor"CauseThe issue occurs from a client script "Check Valid Task Start Date And Set End" which again calls a User Interface (UI) Script PmClientDateAndDurationHandlerBoth the Client Script and the User Interface (UI) Script are Out of the box But found the Global User Interface (UI) scripts which are customized in affected instanceResolutionCheck the Global UI Scripts and filter with the custom scripts. Try deactivating custom UI Scripts which can be the most probable root cause of such types of issues.