Unable to drag mapped items to new heiarchy

I have an issue where the heiarchy of an object has changed.

The original mapped item is like this:

Aliases.TestAPP.TestAppForm.MainPanel.mainControlPanel.MainTabControl.Setup.setupTabControl.HourRestrictionsSetup.hourRestrictionSplitContainerPanel.hourRestrictionsSplitContainer.SplitterPanel1.hourRestrictionsAssignmentGrid

Now it's has two additional levels like this

Aliases.TestApp.TestAppForm.MainPanel.mainControlPanel.MainTabControl.Setup.setupTabControl.SetupHours.setupHoursTabControl.HourRestrictionsSetup.hourRestrictionSplitContainerPanel.hourRestrictionsSplitContainer.SplitterPanel.hourRestrictionsAssignmentGrid

As you can see it's added .SetupHours.setupHoursTabControl.

I tried following the directions here by dragging the old mapped heiarchy to the new one but when trying it gives me a circle with a line through it.

Any ideas on how to do this?

I have attached a screenshot, the top arrow shows the original heicarchy, the bottom is the newer