diff --git a/chrome/content/zotero/fileInterface.js b/chrome/content/zotero/fileInterface.js
index bddb6ec687..5c8581ae82 100644
--- a/chrome/content/zotero/fileInterface.js
+++ b/chrome/content/zotero/fileInterface.js
@@ -743,6 +743,8 @@ var Zotero_File_Interface = new function() {
 	 * @param {Boolean} [asCitations=false] - Copy citation cluster instead of bibliography
 	 */
 	this.copyItemsToClipboard = function (items, style, locale, asHTML, asCitations) {
+		var d = new Date();
+		
 		// copy to clipboard
 		var transferable = Components.classes["@mozilla.org/widget/transferable;1"].
 						   createInstance(Components.interfaces.nsITransferable);
@@ -792,6 +794,8 @@ var Zotero_File_Interface = new function() {
 		transferable.setTransferData("text/unicode", str, output.length * 2);
 		
 		clipboardService.setData(transferable, null, Components.interfaces.nsIClipboard.kGlobalClipboard);
+		
+		Zotero.debug(`Copied bibliography to clipboard in ${new Date() - d} ms}`);
 	}
 	
 	
diff --git a/chrome/content/zotero/tools/cslpreview.js b/chrome/content/zotero/tools/cslpreview.js
index 6bece83dca..dc177dd966 100644
--- a/chrome/content/zotero/tools/cslpreview.js
+++ b/chrome/content/zotero/tools/cslpreview.js
@@ -53,6 +53,7 @@ var Zotero_CSL_Preview = new function() {
 		progressWin.show();
 		progressWin.startCloseTimer();
 		var f = function() {
+			var d = new Date();
 			var styles = Zotero.Styles.getVisible();
 			// XXX needs its own string really for the title!
 			var str = '<html><head><title></title></head><body>';
@@ -78,7 +79,9 @@ var Zotero_CSL_Preview = new function() {
 			}
 			
 			str += '</body></html>';
-			iframe.contentDocument.documentElement.innerHTML = str;			
+			iframe.contentDocument.documentElement.innerHTML = str;
+			
+			Zotero.debug(`Generated previews in ${new Date() - d} ms`);
 		};
 		// Give progress window time to appear
 		setTimeout(f, 100);