The Don’t Repeat Feature is useful when your Alert Window displays many alerts for the same symbols in fast progression. This function helps to filter these repeated symbols.
Right-click, select Properties, and check Don't Repeat.
Now, you can select a time period, in which a symbol won’t be repeated, or choose not to repeat symbols at all.
Please note that the History Feature ignores this Don’t Repeat function. The History Feature, which you can access via right-click and then History, will, by default, always show all alerts for a symbol.
To filter the historical output in a similar manner, choose your historical Timeframe. Thereafter, double-click on any of the column headers, to bring up the Group and Sort Menu.
Here, select Keep Newest, to only see the last alert for a stock, or Keep Oldest, to only see the very first alert that triggered for a symbol, from the Symbol Options dropdown.