The JSF/Seam stack used in the Nuxeo Platform uses server-side state saving: for each JSF component in the tree of graphical components, a state is saved server-side.
Each JSF component tree state is associated to a unique identifier, and the number of states is configurable using the JSF parameters com.sun.faces.numberOfViewsInSession and com.sun.faces.numberOfLogicalViews.
When the number of clicks exceeds this number of states, the page cannot be restored, and JSF may throw a ViewExpiredException.
Since version 5.7.1 (and 5.6.0-HF12), the default value in the Nuxeo Platform is set to 4 for both parameters (instead of 50 which was the previous default value) because it has an impact on performance.
Since version 5.7.2 (and 5.6.0-HF20), these values can be changed by adding (for example) the following line to the nuxeo.conf file:
nuxeo.jsf.numberOfViewsInSession=25
nuxeo.jsf.numberOfLogicalViews=25
Related JIRA issues: