diff --git a/copyparty/svchub.py b/copyparty/svchub.py
index c31f2ee5..8983d423 100644
--- a/copyparty/svchub.py
+++ b/copyparty/svchub.py
@@ -9,7 +9,6 @@ from datetime import datetime, timedelta
 import calendar
 
 from .__init__ import PY2, WINDOWS, MACOS, VT100
-from .authsrv import AuthSrv
 from .tcpsrv import TcpSrv
 from .up2k import Up2k
 from .util import mp
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index 9c1f159b..86a90668 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -64,7 +64,7 @@ class Up2k(object):
         self.flags = {}
         self.cur = {}
         self.mtag = None
-        self.n_mtag_tags_added = 0
+        self.n_mtag_tags_added = -1
 
         self.mem_cur = None
         self.sqlite_ver = None
@@ -461,7 +461,10 @@ class Up2k(object):
                 # mp.pool.ThreadPool and concurrent.futures.ThreadPoolExecutor
                 # both do crazy runahead so lets reinvent another wheel
                 nw = os.cpu_count() if hasattr(os, "cpu_count") else 4
-                self.log("using {}x {}".format(nw, self.mtag.backend))
+                if self.n_mtag_tags_added == -1:
+                    self.log("using {}x {}".format(nw, self.mtag.backend))
+                    self.n_mtag_tags_added = 0
+
                 mpool = Queue(nw)
                 for _ in range(nw):
                     thr = threading.Thread(target=self._tag_thr, args=(mpool,))
diff --git a/copyparty/web/browser.js b/copyparty/web/browser.js
index d36c9cdf..cdf25ff3 100644
--- a/copyparty/web/browser.js
+++ b/copyparty/web/browser.js
@@ -467,8 +467,7 @@ function play(tid, call_depth) {
 		var o = ebi(oid);
 		o.setAttribute('id', 'thx_js');
 		if (window.history && history.replaceState) {
-			var nurl = (document.location + '').split('#')[0] + '#' + oid;
-			hist_replace(ebi('files').innerHTML, nurl);
+			hist_replace((document.location + '').split('#')[0] + '#' + oid);
 		}
 		else {
 			document.location.hash = oid;
@@ -726,7 +725,6 @@ function autoplay_blocked() {
 
 // tree
 (function () {
-	var treedata = null;
 	var dyn = bcfg_get('dyntree', true);
 	var treesz = icfg_get('treesz', 16);
 	treesz = Math.min(Math.max(treesz, 4), 50);
@@ -746,13 +744,15 @@ function autoplay_blocked() {
 		treefiles.appendChild(ebi('epi'));
 
 		swrite('entreed', 'tree');
-		get_tree("", get_vpath());
+		get_tree("", get_vpath(), true);
 	}
 
-	function get_tree(top, dst) {
+	function get_tree(top, dst, rst) {
 		var xhr = new XMLHttpRequest();
 		xhr.top = top;
 		xhr.dst = dst;
+		xhr.rst = rst;
+		xhr.ts = new Date().getTime();
 		xhr.open('GET', dst + '?tree=' + top, true);
 		xhr.onreadystatechange = recvtree;
 		xhr.send();
@@ -768,6 +768,13 @@ function autoplay_blocked() {
 			return;
 		}
 
+		var cur = ebi('treeul').getAttribute('ts');
+		if (cur && parseInt(cur) > this.ts) {
+			console.log("reject tree");
+			return;
+		}
+		ebi('treeul').setAttribute('ts', this.ts);
+
 		var top = this.top == '.' ? this.dst : this.top,
 			name = top.split('/').slice(-2)[0],
 			rtop = top.replace(/^\/+/, "");
@@ -781,7 +788,7 @@ function autoplay_blocked() {
 		var html = parsetree(res, rtop);
 		if (!this.top) {
 			html = '<li><a href="#">-</a><a href="/">[root]</a>\n<ul>' + html;
-			if (!ebi('treeul').getElementsByTagName('li').length)
+			if (this.rst || !ebi('treeul').getElementsByTagName('li').length)
 				ebi('treeul').innerHTML = html + '</ul></li>';
 		}
 		else {
@@ -841,12 +848,20 @@ function autoplay_blocked() {
 			treegrow.call(this.previousSibling, e);
 			return;
 		}
+		reqls(this.getAttribute('href'), true);
+	}
+
+	function reqls(url, hpush) {
 		var xhr = new XMLHttpRequest();
-		xhr.top = this.getAttribute('href');
+		xhr.top = url;
+		xhr.hpush = hpush;
+		xhr.ts = new Date().getTime();
 		xhr.open('GET', xhr.top + '?ls', true);
 		xhr.onreadystatechange = recvls;
 		xhr.send();
-		get_tree('.', xhr.top);
+		if (hpush)
+			get_tree('.', xhr.top);
+
 		enspin('#files');
 	}
 
@@ -874,6 +889,13 @@ function autoplay_blocked() {
 			return;
 		}
 
+		var cur = ebi('files').getAttribute('ts');
+		if (cur && parseInt(cur) > this.ts) {
+			console.log("reject ls");
+			return;
+		}
+		ebi('files').setAttribute('ts', this.ts);
+
 		try {
 			var res = JSON.parse(this.responseText);
 		}
@@ -913,7 +935,9 @@ function autoplay_blocked() {
 		html = html.join('\n');
 		ebi('files').innerHTML = html;
 
-		hist_push(html, this.top);
+		if (this.hpush)
+			hist_push(this.top);
+
 		apply_perms(res.perms);
 		despin('#files');
 
@@ -994,19 +1018,13 @@ function autoplay_blocked() {
 		entree();
 
 	window.onpopstate = function (e) {
-		console.log(e.url + ' ,, ' + ((e.state + '').slice(0, 64)));
-		var html = sessionStorage.getItem(e.state || 1);
-		if (!html)
-			return;
-
-		ebi('files').innerHTML = html;
-		reload_tree();
-		reload_browser();
+		console.log("h-pop " + e.state);
+		get_tree("", e.state, true);
+		reqls(e.state);
 	};
 
 	if (window.history && history.pushState) {
-		var u = get_vpath() + window.location.hash;
-		hist_replace(ebi('files').innerHTML, u);
+		hist_replace(get_vpath() + window.location.hash);
 	}
 })();
 
diff --git a/copyparty/web/util.js b/copyparty/web/util.js
index 719f608a..cff90ff5 100644
--- a/copyparty/web/util.js
+++ b/copyparty/web/util.js
@@ -335,14 +335,12 @@ function bcfg_upd_ui(name, val) {
 }
 
 
-function hist_push(html, url) {
-    var key = new Date().getTime();
-    sessionStorage.setItem(key, html);
-    history.pushState(key, url, url);
+function hist_push(url) {
+    console.log("h-push " + url);
+    history.pushState(url, url, url);
 }
 
-function hist_replace(html, url) {
-    var key = new Date().getTime();
-    sessionStorage.setItem(key, html);
-    history.replaceState(key, url, url);
+function hist_replace(url) {
+    console.log("h-repl " + url);
+    history.replaceState(url, url, url);
 }