diff --git a/chrome/content/zotero/zoteroPane.xul b/chrome/content/zotero/zoteroPane.xul
index 63eccc0fc..4f4b82dd1 100644
--- a/chrome/content/zotero/zoteroPane.xul
+++ b/chrome/content/zotero/zoteroPane.xul
@@ -144,13 +144,13 @@
 								onpopuphidden="Zotero_Lookup.onHidden(event)">
 							<vbox>
 								<description>&zotero.lookup.description;</description>
-								<vbox id="zotero-lookup-singleLine">
+								<vbox id="zotero-lookup-singleLine" flex="1">
 									<stack>
 										<progressmeter id="zotero-lookup-progress" mode="undetermined" collapsed="true"/>
 										<textbox id="zotero-lookup-textbox" onkeypress="return Zotero_Lookup.onKeyPress(event, this)" oninput="Zotero_Lookup.adjustTextbox(this)" flex="1" newlines="pasteintact"/>
 									</stack>
 								</vbox>
-								<vbox id="zotero-lookup-multiline" collapsed="true">
+								<vbox id="zotero-lookup-multiline" collapsed="true" flex="1">
 									<textbox id="zotero-lookup-multiline-textbox" onkeypress="return Zotero_Lookup.onKeyPress(event, this)" multiline="true" rows="5" wrap="off" flex="1"/>
 									<hbox align="start" id="zotero-lookup-buttons" class="zotero-button-clear-image">
 										<button label="&zotero.lookup.button.search;" align="start" oncommand="Zotero_Lookup.accept(document.getElementById('zotero-lookup-multiline-textbox'))"/>