Action should be able to hold a state. State is persistent compared to the onTriggered() value. State allows us to do more complex interaction with the external platform components.
Currently the PreviewAction does all the previews "live;" the values update continuously and the application is expected to generate the preview on constantly.
This can be problematic if the application is unable to generate a preview or generating the preview is so expensive resource-wise that it's not feasible to do a live preview.
In the future the PreviewAction will offer more preview modes which allows the developer to specify manual or partial previews.
Currently the PreviewAction does not offer a way to control the layout of the PreviewParameters. In the future a layout support could be added.
Currently the only supported preview parameter is the PreviewRangeParameter. We need more parameter types like Text, Boolean and ListSelection.
Application should be able to provide their own custom toolbar items in the HUD toolbar.