diff --git a/chrome/content/zotero/xpcom/reader.js b/chrome/content/zotero/xpcom/reader.js
index f3b69cbd74..5c6d67f228 100644
--- a/chrome/content/zotero/xpcom/reader.js
+++ b/chrome/content/zotero/xpcom/reader.js
@@ -1309,6 +1309,7 @@ class ReaderTab extends ReaderInstance {
 		this._iframe.setAttribute('type', 'content');
 		this._iframe.setAttribute('src', 'resource://zotero/pdf-reader/viewer.html');
 		this._tabContainer.appendChild(this._iframe);
+		this._iframe.docShell.windowDraggingAllowed = true;
 		
 		this._popupset = this._window.document.createXULElement('popupset');
 		this._tabContainer.appendChild(this._popupset);
@@ -1407,6 +1408,7 @@ class ReaderWindow extends ReaderInstance {
 				this._window.onGoMenuOpen = this._onGoMenuOpen.bind(this);
 				this._window.onViewMenuOpen = this._onViewMenuOpen.bind(this);
 				this._iframe = this._window.document.getElementById('reader');
+				this._iframe.docShell.windowDraggingAllowed = true;
 			}
 
 			if (this._iframe.contentWindow && this._iframe.contentWindow.document === event.target) {
diff --git a/pdf-reader b/pdf-reader
index 43ac12bd28..5c21f0a43b 160000
--- a/pdf-reader
+++ b/pdf-reader
@@ -1 +1 @@
-Subproject commit 43ac12bd289b43dbebc136c15aeb0223210ba9bf
+Subproject commit 5c21f0a43b328bb53e290954e67fe59a54401bf1