Add class when review panel should layout to the left.

services/web/app/views/project/editor/editor.jade

@@ -18,6 +18,7 @@ div.full-size(
 			'rp-state-overview': (reviewPanel.subView === SubViews.OVERVIEW),\
 			'rp-size-mini': (!ui.reviewPanelOpen && reviewPanel.hasEntries),\
 			'rp-size-expanded': ui.reviewPanelOpen\
+			'rp-layout-left': reviewPanel.layoutToLeft
 		}"
 	)
 		.loading-panel(ng-show="!editor.sharejs_doc || editor.opening")

services/web/public/coffee/ide/review-panel/controllers/ReviewPanelController.coffee

@@ -22,6 +22,16 @@ define [
 				loading: false
 			commentThreads: {}
 			resolvedThreadIds: {}
+			layoutToLeft: false
+
+		$scope.$on "layout:pdf:linked", (event, state) ->
+			$scope.reviewPanel.layoutToLeft = (state.east?.size < 220 || state.east?.initClosed)
+
+		$scope.$on "layout:pdf:resize", (event, state) ->
+			$scope.reviewPanel.layoutToLeft = (state.east?.size < 220 || state.east?.initClosed)
+
+		$scope.$watch "ui.pdfLayout", (layout) ->
+			$scope.reviewPanel.layoutToLeft = (layout == "flat")
 
 		$scope.commentState =
 			adding: false