diff --git a/src/common/DayGrid.limit.js b/src/common/DayGrid.limit.js
index 59adec6..3af4390 100644
--- a/src/common/DayGrid.limit.js
+++ b/src/common/DayGrid.limit.js
@@ -234,6 +234,7 @@ $.extend(DayGrid.prototype, {
 			parentEl: this.el,
 			top: topEl.offset().top,
 			autoHide: true, // when the user clicks elsewhere, hide the popover
+			viewportConstrain: view.opt('popoverViewportConstrain'),
 			hide: function() {
 				// destroy everything when the popover is hidden
 				_this.segPopover.destroy();
diff --git a/src/common/Popover.js b/src/common/Popover.js
index d7bcb43..dab2d62 100644
--- a/src/common/Popover.js
+++ b/src/common/Popover.js
@@ -141,10 +141,12 @@ Popover.prototype = {
 		viewportLeft += windowEl.scrollLeft();
 
 		// constrain to the view port. if constrained by two edges, give precedence to top/left
-		top = Math.min(top, viewportTop + viewportEl.outerHeight() - height - this.margin);
-		top = Math.max(top, viewportTop + this.margin);
-		left = Math.min(left, viewportLeft + viewportEl.outerWidth() - width - this.margin);
-		left = Math.max(left, viewportLeft + this.margin);
+		if (options.viewportConstrain !== false) {
+			top = Math.min(top, viewportTop + viewportEl.outerHeight() - height - this.margin);
+			top = Math.max(top, viewportTop + this.margin);
+			left = Math.min(left, viewportLeft + viewportEl.outerWidth() - width - this.margin);
+			left = Math.max(left, viewportLeft + this.margin);
+		}
 
 		this.el.css({
 			top: top - origin.top,