diff --git a/mozilla/editor/ui/composer/content/editorOverlay.xul b/mozilla/editor/ui/composer/content/editorOverlay.xul
index 3ceb24c9ce8..c976715d1cf 100644
--- a/mozilla/editor/ui/composer/content/editorOverlay.xul
+++ b/mozilla/editor/ui/composer/content/editorOverlay.xul
@@ -835,7 +835,7 @@
   <tab id="TagModeButton"      class="tab-bottom edit-mode _plain" type="text" selected="0" label="&AllTagsMode.label;"    oncommand="SetEditMode(2);"
           tooltiptext="&AllTagsMode.tooltip;"/>
   <tab id="SourceModeButton"   class="tab-bottom edit-mode _plain" type="text" selected="0" label="&SourceMode.label;"     oncommand="SetEditMode(3);"
-          tooltiptext="&HTMLSourceMode.tooltip;"/>
+          tooltiptext="&HTMLSourceMode.tooltip;" dir="&SourceTabDirection;"/>
   <tab id="PreviewModeButton"  class="tab-bottom edit-mode _plain" type="text" selected="0" label="&PreviewMode.label;"    oncommand="SetEditMode(0);"
           tooltiptext="&PreviewMode.tooltip;"/>
 
diff --git a/mozilla/editor/ui/composer/locale/en-US/editorOverlay.dtd b/mozilla/editor/ui/composer/locale/en-US/editorOverlay.dtd
index f70c108dc00..b598d2701cb 100644
--- a/mozilla/editor/ui/composer/locale/en-US/editorOverlay.dtd
+++ b/mozilla/editor/ui/composer/locale/en-US/editorOverlay.dtd
@@ -670,6 +670,14 @@
 <!ENTITY PreviewMode.accesskey "p">
 <!ENTITY PreviewMode.tooltip "Display as WYSIWYG (as in Navigator)">
 
+<!-- LOCALIZATION NOTE: Do NOT translate text for 'SourceTabDirection'
+     Use latin "ltr" if you want the <html> image to left of the 
+     'SourceMode.label' text defined above,
+     or use latin "rtl" if you want this image to the right of text
+     This is the value of the HTML 'dir' attribute
+-->
+<!ENTITY SourceTabDirection "ltr">
+
 <!-- Smiley Menu items -->
 <!ENTITY smiley1Cmd.label "Smile">
 <!ENTITY smiley2Cmd.label "Frown">
