Add directive to collapse elements via height.

services/web/app/views/project/editor/review-panel.pug

@@ -100,7 +100,9 @@
 				)
 					i.fa.fa-angle-down
 
-			.rp-overview-file-entries(ng-class="{ 'rp-overview-file-entries-collapsed' : reviewPanel.overview.docsCollapsedState[doc.doc.id] }")
+			.rp-overview-file-entries(
+				review-panel-collapse-height="reviewPanel.overview.docsCollapsedState[doc.doc.id]"
+			)
 				.rp-entry-wrapper(
 					ng-repeat="(entry_id, entry) in reviewPanel.entries[doc.doc.id] | orderOverviewEntries"
 					ng-if="!(entry.type === 'comment' && reviewPanel.commentThreads[entry.thread_id].resolved === true)"

services/web/public/coffee/ide/review-panel/ReviewPanelManager.coffee

@@ -8,6 +8,7 @@ define [
 	"ide/review-panel/directives/addCommentEntry"
 	"ide/review-panel/directives/resolvedCommentEntry"
 	"ide/review-panel/directives/resolvedCommentsDropdown"
+	"ide/review-panel/directives/reviewPanelCollapseHeight"
 	"ide/review-panel/filters/notEmpty"
 	"ide/review-panel/filters/orderOverviewEntries"
 ], () ->

services/web/public/stylesheets/app/editor/review-panel.less

@@ -575,10 +575,16 @@
 		transform: rotateZ(0deg);
 		transition: transform 0.15s ease
 	}
+	
 	.rp-overview-file-header-collapse-on {
 		transform: rotateZ(180deg);
 	}
 
+	.rp-overview-file-entries {
+		overflow: hidden;
+		transition: height .15s;
+	}
+
 .rp-comment-wrapper {
 	transition: .35s opacity ease-out .2s;