Comparing on column 'Size':

Caused by: java.lang.NullPointerException
	at org.hippoecm.frontend.plugins.gallery.columns.compare.SizeComparator.compare(SizeComparator.java:38)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:44)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:27)
	at java.util.TimSort.binarySort(TimSort.java:265)
	at java.util.TimSort.sort(TimSort.java:190)
	at java.util.TimSort.sort(TimSort.java:173)
	at java.util.Arrays.sort(Arrays.java:659)
	at java.util.Collections.sort(Collections.java:217)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.load(DocumentsProvider.java:156)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.size(DocumentsProvider.java:77)
	at org.apache.wicket.markup.repeater.data.DataViewBase.internalGetItemCount(DataViewBase.java:141)
	
	
Comparing on column 'Mimetype':

java.lang.NullPointerException
	at org.hippoecm.frontend.plugins.gallery.columns.compare.MimeTypeComparator.compare(MimeTypeComparator.java:35)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:44)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:27)
	at java.util.TimSort.binarySort(TimSort.java:265)
	at java.util.TimSort.sort(TimSort.java:190)
	at java.util.TimSort.sort(TimSort.java:173)
	at java.util.Arrays.sort(Arrays.java:659)
	at java.util.Collections.sort(Collections.java:217)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.load(DocumentsProvider.java:156)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.size(DocumentsProvider.java:77)
	at org.apache.wicket.markup.repeater.data.DataViewBase.internalGetItemCount(DataViewBase.java:141)
	
Comparing on column 'Last modified' 	

java.lang.NullPointerException
	at org.hippoecm.frontend.plugins.gallery.columns.compare.CalendarComparator.compare(CalendarComparator.java:35)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:44)
	at org.hippoecm.frontend.plugins.gallery.columns.compare.PropertyComparator.compare(PropertyComparator.java:27)
	at java.util.TimSort.binarySort(TimSort.java:265)
	at java.util.TimSort.sort(TimSort.java:190)
	at java.util.TimSort.sort(TimSort.java:173)
	at java.util.Arrays.sort(Arrays.java:659)
	at java.util.Collections.sort(Collections.java:217)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.load(DocumentsProvider.java:156)
	at org.hippoecm.frontend.plugins.standards.list.DocumentsProvider.size(DocumentsProvider.java:77)
	at org.apache.wicket.markup.repeater.data.DataViewBase.internalGetItemCount(DataViewBase.java:141)