Deleting table items may cause references to be broken. In this case a Ghost item will be created to maintain application integrity until the developer can resolve the broken references.
A Ghost can be recognized by the following icon:
In this guide a ghost of an attribute is used as example. Ghosts of filters, selectors, metrics, and actions can also exist.
Normally, you should try to avoid causing ghosts.
Deleting the expression attribute that is used in a dashboard will lead to a broken reference. A Ghost item will be created to maintain application integrity.
In the lower left-hand corner of the application the Tools panel shows that there is a problem in the application. The ghost will be displayed in the Errors tab of the Tools panel. See illustration below.
See illustration below.
Ghost items must not be deleted while there are still references to it from the application. To remove a ghost, you must first replace all references to it.
Never attempt to delete a ghost while there are still references to it!
Doing so may irreparably break your application.
Follow this step to see all active references to a ghost attribute.
Double click on the ghost item in the table item list.
The Tools panel shows all references to the ghost item. See illustration below for an example.
You can view the references for any item by right clicking and selecting Advanced > Show references…, or by using the Find In Application dialog (Ctrl+Shift+F).
When a ghost item is no longer referenced anywhere, it can be safely removed from the application.
Follow these steps to remove a ghost.
Click on the logo icon and select Advanced > Delete unused ghosts.
A ghost can also be removed by right clicking and selecting Delete. In this case you must verify that there are no references left to the ghost.
Updated about a year ago