diff --git a/modules/ve/ce/ve.ce.Surface.js b/modules/ve/ce/ve.ce.Surface.js
index de4b467b55..bf24cd9388 100644
--- a/modules/ve/ce/ve.ce.Surface.js
+++ b/modules/ve/ce/ve.ce.Surface.js
@@ -184,6 +184,7 @@ ve.ce.Surface.static.getClipboardHash = function ( $elements ) {
  * Get the coordinates of the selection anchor.
  *
  * @method
+ * @returns {Object|null} { 'start': { 'x': ..., 'y': ... }, 'end': { 'x': ..., 'y': ... } }
  */
 ve.ce.Surface.prototype.getSelectionRect = function () {
 	var sel, rect, $span, lineHeight, startRange, startOffset, endRange, endOffset, focusedOffset;
diff --git a/modules/ve/ui/ve.ui.Context.js b/modules/ve/ui/ve.ui.Context.js
index 2a34601a53..05a272bb1c 100644
--- a/modules/ve/ui/ve.ui.Context.js
+++ b/modules/ve/ui/ve.ui.Context.js
@@ -294,6 +294,14 @@ ve.ui.Context.prototype.updateDimensions = function ( transition ) {
 		// We're on top of a selected text
 		// Get the position of the cursor
 		cursorPosition = surface.getSelectionRect();
+		if ( !cursorPosition ) {
+			// The surface apparently isn't selected, so getSelectionRect() returned null.
+			// This shouldn't happen because the context is only supposed to be displayed in
+			// response to a selection, but for some reason this does happen in phantomjs.
+			// We can't update the context position if we don't know where the selection is,
+			// so just bail.
+			return this;
+		}
 
 		// Correct for surface offset:
 		position = {
diff --git a/modules/ve/ui/ve.ui.SurfaceToolbar.js b/modules/ve/ui/ve.ui.SurfaceToolbar.js
index d120338ff9..d76c7c9617 100644
--- a/modules/ve/ui/ve.ui.SurfaceToolbar.js
+++ b/modules/ve/ui/ve.ui.SurfaceToolbar.js
@@ -130,10 +130,14 @@ ve.ui.SurfaceToolbar.prototype.onWindowResize = function () {
  * the cursor is obscured by the toolbar.
  */
 ve.ui.SurfaceToolbar.prototype.onSurfaceViewKeyUp = function () {
-	var cursorPos = this.surface.view.getSelectionRect(),
-		barHeight = this.$bar.height(),
-		scrollTo = this.$bar.offset().top - barHeight + ( cursorPos.end.y - cursorPos.start.y ),
-		obscured = cursorPos.start.y - this.$window.scrollTop() < barHeight;
+	var barHeight, scrollTo, obscured, cursorPos = this.surface.view.getSelectionRect();
+	if ( !cursorPos ) {
+		return;
+	}
+
+	barHeight = this.$bar.height();
+	scrollTo = this.$bar.offset().top - barHeight + ( cursorPos.end.y - cursorPos.start.y );
+	obscured = cursorPos.start.y - this.$window.scrollTop() < barHeight;
 
 	// If toolbar is floating and cursor is obscured, scroll cursor into view
 	if ( obscured && this.floating ) {