diff --git a/suite/common/directory/directory.xul b/suite/common/directory/directory.xul
index ca649c2cc65b..f8548348a0c8 100644
--- a/suite/common/directory/directory.xul
+++ b/suite/common/directory/directory.xul
@@ -32,7 +32,7 @@
 
   <html:script src="directory.js" />
 
-  <html:div flex="1">
+  <html:div style="width:100px;height:100px;" flex="1">
     <tree id="tree" datasources="rdf:null" style="height:100%;">
       <template>
         <treechildren>
diff --git a/xpfe/components/directory/directory.xul b/xpfe/components/directory/directory.xul
index ca649c2cc65b..f8548348a0c8 100644
--- a/xpfe/components/directory/directory.xul
+++ b/xpfe/components/directory/directory.xul
@@ -32,7 +32,7 @@
 
   <html:script src="directory.js" />
 
-  <html:div flex="1">
+  <html:div style="width:100px;height:100px;" flex="1">
     <tree id="tree" datasources="rdf:null" style="height:100%;">
       <template>
         <treechildren>