diff --git a/mailnews/addrbook/resources/content/addressbook.xul b/mailnews/addrbook/resources/content/addressbook.xul
index 12009b5ac6f..b8f098e67b5 100644
--- a/mailnews/addrbook/resources/content/addressbook.xul
+++ b/mailnews/addrbook/resources/content/addressbook.xul
@@ -251,11 +251,9 @@ Rights Reserved.
 	<box orient="horizontal" flex="100%" style="min-width:150px">
 		<!-- sidebar with dir tree -->
 		<box id="sidebar-box">
-			<splitter class="sidebarheader-main" collapse="after">
 				<sidebarheader class="sidebarheader-main" value="&addressbook-sidebar-header.label;"/>
-			</splitter>
 			
-			<tree id="dirTree" flex="1"/>
+			<tree id="dirTree" flex="1000"/>
 		</box>
 		<splitter id="sidebar-splitter" collapse="before" persist="state"/>
 		
@@ -281,4 +279,4 @@ Rights Reserved.
 	
 	<box id="taskbar" class="toolbox-bottom"/>
 
-</window>
\ No newline at end of file
+</window>
diff --git a/mailnews/base/resources/content/messenger.xul b/mailnews/base/resources/content/messenger.xul
index 8d7137be615..0d347d292b2 100644
--- a/mailnews/base/resources/content/messenger.xul
+++ b/mailnews/base/resources/content/messenger.xul
@@ -326,10 +326,8 @@ Rights Reserved.
 
 	<box align="horizontal" style="height:100px" flex="1">
 		<box id="sidebar-box">
-			<splitter class="sidebarheader-main" collapse="after" persist="state">
-				<sidebarheader class="sidebarheader-main" value="&mail-sidebar-header.label;"/>
-			</splitter>
-			<tree id="folderTree" style="width:100px; height: 600px;" flex="1" context="folderPaneContext"/>
+			<sidebarheader class="sidebarheader-main" value="&mail-sidebar-header.label;"/>
+			<tree id="folderTree" flex="1000" context="folderPaneContext" />
 		</box>
           
 		<splitter id="sidebar-splitter"/>