In SmartClient version 7.0RC2, an issue exists whereby if screenReader support has been enabled via setting isc.screenReader = true;, attempting to render out a Calendar component will cause errors.

This has been resolved internally and the fix will be present in the 7.0 final release. In the meantime, here's a patch for the 7.0 RC2 build
Code:
//----------------------------------------------------------------------------
// Isomorphic SmartClient 7.0rc2 patch
// Purpose: Fix for an error screenReader and Calendar components.
// 
// Applies to SmartClient 7.0RC2 builds only
//----------------------------------------------------------------------------

if (window.isc && isc.version.startsWith('7.0rc2')) {
    if (isc.ListGrid) {
        isc.ListGrid.addMethods({
            getRowWAIState : function (rowNum) {
                var record = this.getRecord(rowNum);
                if (this.selection && this.selection.isSelected && this.selection.isSelected(rowNum)) {
                    return {selected : true };
                }
            }
        });
    }
} else if (window.isc) {
    isc.Log.logWarn("Patch for SmartClient 7.0 Release Candidate 2 included in this application. " +
            "You are currently running SmartClient verion '"+ isc.version + 
            "'. This patch is not compatible with this build and will have no effect. " +
            "It should be removed from your application source.");
}