The behavior is most often caused by an issue with Silverlight. If one were to hit F12 as they opened GIFTS Online and then took the steps to reproduce the issue, one would notice an error appear on their screen related to Silverlight coming from their browser.
This error is often alike to the one below:
"SCRIPT5022: Unhandled Error in Silverlight Application
Message: System.Exception: [Arg_COMException]
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=5.1.50901.00&File=mscorlib.dll&Key=Arg_COMException
at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
at MS.Internal.XcpImports.FrameworkElement_MeasureOverride(FrameworkElement element, Size availableSize)
at Infragistics.Controls.Editors.ComboEditorItemControl.MeasureOverride(Size availableSize)
at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)"
Since this is not directly a GIFTS-related issue, we would suggest bringing this error to the attention of your IT department. To assist them, here are some resources related to fixing this error: