You want your Klip to always show users the latest data every time it refreshes. If an item disappears from the data source, it should disappear from the Klip on next refresh.
A dashboard Klip should:
a. display the latest data in the Klip; and
b. keep items in the Klip as long as they are in the source, regardless of the user's Item Management setting.
Your users are still able to manually remove items, and items are dimmed when they have been visited.
a. Displaying the latest data<html>
<setup>
<purge>
permanent
</purge>
</setup>
</html>
When <purge> is set to permanent, an item that is no longer in the data source is automatically removed from the Klip. If it reappears in the source, it will be displayed again.
If you do not want the deleted item that reappeared in the data source to be displayed again, set <purge> to true instead.
b. Keeping the old data in the Klip
You can additionally ensure that items that are in the data source are not removed from the Klip. Normally, Klipfolio Dashboard's global item management removes old items based on the user's settings in the Items tab of the Options window.

<html>
<setup>
<purge>
permanent
</purge>
<autoremove>
false
</autoremove>
</setup>
</html>
Additional control
Using <autoremove> still allows users to manually remove items. Manually removed items will not come back on subsequent refreshes. In addition, items that have been clicked are dimmed to indicate that they have been visited.
If you'd like to also remove these options, you can use the CSS property persistence instead of <autoremove>. Setting the persistence property to dashboard will add the following behaviour to the Klip:
<style>
report {
type: item;
persistence: dashboard;
}
...
</style>