The Debug -> Page ViewState tab is displayed only when page ViewState debugging is enabled. This can be achieved either by configuring certain settings in Site Manager -> Settings -> System -> Debug, or by adding specific keys to the appSettings section of your project's web.config file. Both options are described in this context help topic.
On this tab, you can see the ViewState of particular controls on recently loaded pages. In the Control ID column, you can see the ID of each control on the requested page. The Is dirty column indicates if the item was added to the ViewState after the TrackViewState() method was called (typically occurs during OnInit). You can display only controls with such items by enabling the Show only controls with dirty values check-box above the grid. The ViewState column displays the control's ViewState data and the Total size column contains information about the total size of the control's ViewState data.
The log can be cleared using the Clear ViewState log button.
Please note: ViewState of the controls is retrieved using reflection. Therefore this debug may not work properly under medium trust environment or other specific circumstances.
For more information about debugging in Kentico CMS, please refer to Developer's Guide -> Development -> Debugging and system information.