diff --git a/src/pretix/presale/templates/pretixpresale/event/index.html b/src/pretix/presale/templates/pretixpresale/event/index.html
index 81592b7dea..b2840e6b43 100644
--- a/src/pretix/presale/templates/pretixpresale/event/index.html
+++ b/src/pretix/presale/templates/pretixpresale/event/index.html
@@ -115,7 +115,8 @@
                     browser settings.
                 {% endblocktrans %}
                 <br>
-                <a href="{% eventurl event "presale:event.index" %}" class="btn btn-default" target="_blank">
+                <a href="{% eventurl event "presale:event.index" cart_namespace=cart_namespace %}{% if "cart_id" in request.GET %}?src=widget&take_cart_id={{ request.GET.cart_id }}{% endif %}"
+                        class="btn btn-primary" target="_blank">
                     {% trans "Open ticket shop in new tab" %}
                 </a>
                 <div class="clearfix"></div>
diff --git a/src/pretix/presale/templates/pretixpresale/event/voucher.html b/src/pretix/presale/templates/pretixpresale/event/voucher.html
index cb2bcdb986..8123c4c3d0 100644
--- a/src/pretix/presale/templates/pretixpresale/event/voucher.html
+++ b/src/pretix/presale/templates/pretixpresale/event/voucher.html
@@ -20,10 +20,11 @@
     </p>
     {% if event.presale_is_running or event.settings.show_items_outside_presale_period %}
         <form method="post" data-asynctask
-                action="{% eventurl request.event "presale:event.cart.add" cart_namespace=cart_namespace %}?next={% eventurl request.event "presale:event.index" cart_namespace=cart_namespace %}">
+                action="{% eventurl request.event "presale:event.cart.add" cart_namespace=cart_namespace %}?next={% eventurl request.event "presale:event.index" cart_namespace=cart_namespace %}{% if "iframe" in request.GET %}&iframe={{ request.GET.iframe }}{% endif %}">
             {% csrf_token %}
             <input type="hidden" name="subevent" value="{{ subevent.id|default_if_none:"" }}" />
             <input type="hidden" name="_voucher_code" value="{{ voucher.code }}">
+
             {% for tup in items_by_category %}
                 <section>
                     {% if tup.0 %}
diff --git a/src/pretix/presale/views/cart.py b/src/pretix/presale/views/cart.py
index ccd92cd53c..b9c047f3d4 100644
--- a/src/pretix/presale/views/cart.py
+++ b/src/pretix/presale/views/cart.py
@@ -47,6 +47,9 @@ class CartActionMixin:
             u += '&require_cookie=true'
         else:
             u += '?require_cookie=true'
+        if 'iframe' in self.request.GET:
+            cart_id = get_or_create_cart_id(self.request)
+            u += '&cart_id={}'.format(cart_id)
         return u
 
     def get_success_url(self, value=None):
diff --git a/src/pretix/presale/views/checkout.py b/src/pretix/presale/views/checkout.py
index 1295dd8886..bf00778275 100644
--- a/src/pretix/presale/views/checkout.py
+++ b/src/pretix/presale/views/checkout.py
@@ -1,3 +1,5 @@
+from urllib.parse import quote
+
 from django.contrib import messages
 from django.http import Http404
 from django.shortcuts import redirect
@@ -30,11 +32,11 @@ class CheckoutView(View):
 
         if not cart_exists(request) and "async_id" not in request.GET:
             messages.error(request, _("Your cart is empty"))
-            return redirect(self.get_index_url(self.request))
+            return self.redirect(self.get_index_url(self.request))
 
         if not request.event.presale_is_running:
             messages.error(request, _("The presale for this event is over or has not yet started."))
-            return redirect(self.get_index_url(self.request))
+            return self.redirect(self.get_index_url(self.request))
 
         cart_error = None
         try:
@@ -49,14 +51,13 @@ class CheckoutView(View):
                 continue
             if step.requires_valid_cart and cart_error:
                 messages.error(request, str(cart_error))
-                return redirect(previous_step.get_step_url(request) if previous_step
-                                else self.get_index_url(request))
+                return self.redirect(previous_step.get_step_url(request) if previous_step else self.get_index_url(request))
 
             if 'step' not in kwargs:
-                return redirect(step.get_step_url(request))
+                return self.redirect(step.get_step_url(request))
             is_selected = (step.identifier == kwargs.get('step', ''))
             if "async_id" not in request.GET and not is_selected and not step.is_completed(request, warn=not is_selected):
-                return redirect(step.get_step_url(request))
+                return self.redirect(step.get_step_url(request))
             if is_selected:
                 if request.method.lower() in self.http_method_names:
                     handler = getattr(step, request.method.lower(), self.http_method_not_allowed)
@@ -68,3 +69,8 @@ class CheckoutView(View):
                 step.c_is_before = True
                 step.c_resolved_url = step.get_step_url(request)
         raise Http404()
+
+    def redirect(self, url):
+        if 'cart_id' in self.request.GET:
+            url += ('&' if '?' in url else '?') + 'cart_id=' + quote(self.request.GET.get('cart_id'))
+        return redirect(url)
diff --git a/src/pretix/presale/views/event.py b/src/pretix/presale/views/event.py
index 04dcb85c11..d5e73e85a7 100644
--- a/src/pretix/presale/views/event.py
+++ b/src/pretix/presale/views/event.py
@@ -10,6 +10,7 @@ from django.core.exceptions import PermissionDenied
 from django.db.models import Count, Prefetch, Q
 from django.http import Http404, HttpResponse
 from django.shortcuts import get_object_or_404, redirect
+from django.urls import reverse
 from django.utils.decorators import method_decorator
 from django.utils.timezone import now
 from django.utils.translation import pgettext_lazy, ugettext_lazy as _
@@ -176,7 +177,12 @@ class EventIndex(EventViewMixin, CartMixin, TemplateView):
     template_name = "pretixpresale/event/index.html"
 
     def get(self, request, *args, **kwargs):
+        from pretix.presale.views.cart import get_or_create_cart_id
+
         self.subevent = None
+        if request.GET.get('src', '') == 'widget' and 'take_cart_id' in request.GET:
+            get_or_create_cart_id(request)
+            return redirect(reverse('presale:event.index', kwargs=kwargs))
         if request.event.has_subevents:
             if 'subevent' in kwargs:
                 self.subevent = request.event.subevents.filter(pk=kwargs['subevent'], active=True).first()
diff --git a/src/pretix/static/pretixpresale/js/widget/widget.js b/src/pretix/static/pretixpresale/js/widget/widget.js
index 622819eb21..a69c253c13 100644
--- a/src/pretix/static/pretixpresale/js/widget/widget.js
+++ b/src/pretix/static/pretixpresale/js/widget/widget.js
@@ -696,7 +696,7 @@ var shared_root_computed = {
         if (!this.$root.cart_exists) {
             checkout_url += "checkout/start";
         }
-        var form_target = this.event_url + 'w/' + widget_id + '/cart/add?iframe=1&next=' + checkout_url;
+        var form_target = this.event_url + 'w/' + widget_id + '/cart/add?iframe=1&next=' + encodeURIComponent(checkout_url);
         if (getCookie(this.cookieName)) {
             form_target += "&take_cart_id=" + getCookie(this.cookieName);
         }