fx-compat: Duplicates: UI fixes

- Scroll vertically
- Restore margins between groupboxes
- Restore field version dropmarker

chrome/content/zotero/elements/itemBox.js

@@ -626,6 +626,7 @@
 					button.className = 'zotero-field-version-button';
 					button.setAttribute('image', 'chrome://zotero/skin/treesource-duplicates.png');
 					button.setAttribute('type', 'menu');
+					button.setAttribute('wantdropmarker', true);
 					
 					var popup = button.appendChild(document.createXULElement("menupopup"));
 					

chrome/skin/default/zotero/itemPane.css

@@ -75,9 +75,12 @@
 	font-size: 13px;
 }
 
-#zotero-duplicates-merge-pane > groupbox
-{
-	margin: 0;
+#zotero-duplicates-merge-pane > groupbox {
+	margin: 8px 0 0 0;
+}
+
+#zotero-duplicates-merge-item-box {
+	overflow-y: scroll;
 }
 
 #zotero-duplicates-merge-item-box row