Property search causes an error:

To repeat:

Launch IGB.
Choose a genome.
Click Search tab.
Choose "Properties" in "genome" and enter + search string. Click Search.

Observe the console reports a NullPointerException:

[java] Exception in thread "pool-10-thread-1" java.lang.NullPointerException
[java] at java.lang.String.compareTo(String.java:1167)
[java] at com.affymetrix.igb.search.SearchView$3$1.compare(SearchView.java:503)
[java] at com.affymetrix.igb.search.SearchView$3$1.compare(SearchView.java:501)
[java] at java.util.Arrays.mergeSort(Arrays.java:1270)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1281)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1281)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.mergeSort(Arrays.java:1282)
[java] at java.util.Arrays.sort(Arrays.java:1210)
[java] at java.util.Collections.sort(Collections.java:159)
[java] at com.affymetrix.igb.search.SearchView$3.run(SearchView.java:501)
[java] at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
[java] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
[java] at java.lang.Thread.run(Thread.java:680)