diff --git a/themes/classic/messenger/threadPane.css b/themes/classic/messenger/threadPane.css
index 52a896b5e380..a3241e945634 100644
--- a/themes/classic/messenger/threadPane.css
+++ b/themes/classic/messenger/threadPane.css
@@ -143,8 +143,11 @@ treecol.junkStatusHeader {
   list-style-image: url("chrome://messenger/skin/icons/message-junk-other.gif");
 }
 
+/* "unknown" now looks like "not junk".  see bug #182386 */
 treechildren:-moz-tree-image(junkStatusCol) {
-  list-style-image: url("chrome://messenger/skin/icons/message-junk-unknown.gif");
+  list-style-image: url("chrome://messenger/skin/icons/readmail.gif");
+  padding-left: 0px;
+  padding-right: 4px;
 }
 
 treechildren:-moz-tree-image(junkStatusCol, junk) {
diff --git a/themes/modern/messenger/threadPane.css b/themes/modern/messenger/threadPane.css
index 7cc280915f4b..89f9ccfb94a6 100644
--- a/themes/modern/messenger/threadPane.css
+++ b/themes/modern/messenger/threadPane.css
@@ -187,8 +187,11 @@ treecol.junkStatusHeader {
   list-style-image: url("chrome://messenger/skin/icons/message-junk-other.gif");
 }
 
+/* "unknown" now looks like "not junk".  see bug #182386 */
 treechildren:-moz-tree-image(junkStatusCol) {
-  list-style-image: url("chrome://messenger/skin/icons/message-junk-unknown.gif");
+  list-style-image: url("chrome://messenger/skin/icons/readcol-read.gif");
+  padding-left: 0px;
+  padding-right: 4px;
 }
 
 treechildren:-moz-tree-image(junkStatusCol, junk) {