diff --git a/chrome/content/zotero-platform/mac/itemPane.css b/chrome/content/zotero-platform/mac/itemPane.css
index 5ef0328327..034984e81b 100644
--- a/chrome/content/zotero-platform/mac/itemPane.css
+++ b/chrome/content/zotero-platform/mac/itemPane.css
@@ -6,4 +6,11 @@
 #zotero-feed-item-addTo-button button {
 	margin: 0;
 	-moz-appearance: none;
-}
\ No newline at end of file
+}
+
+/* Show duplicates date list item as selected even when not focused
+   (default behavior on other platforms) */
+#zotero-duplicates-merge-original-date:not(:focus) > richlistitem[selected="true"] {
+	background-color: -moz-cellhighlight;
+	color: -moz-cellhighlighttext;
+}
diff --git a/chrome/content/zotero/elements/itemBox.js b/chrome/content/zotero/elements/itemBox.js
index 60e2f01089..31c3734b74 100644
--- a/chrome/content/zotero/elements/itemBox.js
+++ b/chrome/content/zotero/elements/itemBox.js
@@ -448,11 +448,11 @@
 			}
 			if (this.showTypeMenu) {
 				this.updateItemTypeMenuSelection();
-				this.itemTypeMenu.parentNode.hidden = false;
+				this.itemTypeMenu.parentNode.parentNode.style.display = 'initial';
 				this.itemTypeMenu.setAttribute('ztabindex', '0');
 			}
 			else {
-				this.itemTypeMenu.parentNode.hidden = true;
+				this.itemTypeMenu.parentNode.parentNode.style.display = 'none';
 			}
 			
 			//
@@ -630,7 +630,7 @@
 					var popup = button.appendChild(document.createXULElement("menupopup"));
 					
 					for (let v of this._fieldAlternatives[fieldName]) {
-						var menuitem = document.createXULElement("menuitem");
+						let menuitem = document.createXULElement("menuitem");
 						var sv = Zotero.Utilities.ellipsize(v, 60);
 						menuitem.setAttribute('label', sv);
 						if (v != sv) {
@@ -638,13 +638,13 @@
 						}
 						menuitem.setAttribute('fieldName', fieldName);
 						menuitem.setAttribute('originalValue', v);
-						menuitem.oncommand = () => {
+						menuitem.addEventListener('command', () => {
 							this.item.setField(
 								menuitem.getAttribute('fieldName'),
 								menuitem.getAttribute('originalValue')
 							);
 							this.refresh();
-						};
+						});
 						popup.appendChild(menuitem);
 					}
 					
diff --git a/chrome/content/zotero/zoteroPane.xhtml b/chrome/content/zotero/zoteroPane.xhtml
index c42ec0f2e1..867b6bdff0 100644
--- a/chrome/content/zotero/zoteroPane.xhtml
+++ b/chrome/content/zotero/zoteroPane.xhtml
@@ -1157,13 +1157,13 @@
 												<groupbox id="zotero-duplicates-merge-version-select">
 													<description>&zotero.duplicatesMerge.versionSelect;</description>
 													<hbox>
-														<listbox id="zotero-duplicates-merge-original-date" onselect="Zotero_Duplicates_Pane.setMaster(this.selectedIndex)" rows="0"/>
+														<richlistbox id="zotero-duplicates-merge-original-date" onselect="Zotero_Duplicates_Pane.setMaster(this.selectedIndex)" rows="0"/>
 													</hbox>
 												</groupbox>
 												
 												<groupbox flex="1">
 													<description id="zotero-duplicates-merge-field-select">&zotero.duplicatesMerge.fieldSelect;</description>
-													<zoteroitembox id="zotero-duplicates-merge-item-box" flex="1"/>
+													<item-box id="zotero-duplicates-merge-item-box" flex="1"/>
 												</groupbox>
 											</vbox>
 										</deck>