RC 1.1 is using jQuery v2.1.3. I believe the Calendar jsvsscript contains both a typo and invalid code not compatible with that version of jQuery.
So, for Calendar (both v1.0.16 and dev-master), make the the following changes
calendar_ui.js
line 766, from:
$('#eventtabs').tabs('select', 0);
to:
$('#eventtabs').tabs('option', 0);
Line 2809, from:
$(this).data('autocomplete')._renderItem = function(ul, item) {
to:
$(this).attr('autocomplete')._renderItem = function(ul, item) {
For Tasklist
tasklist.js
line 1312, from:
$('#taskedit').tabs('select', 0);
to:
$('#taskedit').tabs('option', 0);