By default, Orion/HCO is limited to 10 time travel maps which is controlled by the MapsHistoryMaxMaps setting in the advanced configuration ( /Orion/Admin/AdvancedConfiguration/Global.aspx ). After this limit is reached, the button to enable history tracking while editing maps simply stops responding. Some sort of message in the UI saying that you hit this limit would be great so we could avoid dumping a bunch of time into troubleshooting the issue.
