iQC -- When can I Double-Click on a Measurement to Select it?

Software keeps track of the first 1000 measurement stored. Within this set, you may click on any sample to select. Software will display more than 1000 samples but does not allow for unique selection of the other, higher numbered items. If you click on sample 999, it will be selected. If you click on any sample greater than 1000 then the entire set is highlighted.