diff --git a/lms/static/sass/discussion/views/_thread.scss b/lms/static/sass/discussion/views/_thread.scss
index 7570e9e426..a1aaddcc79 100644
--- a/lms/static/sass/discussion/views/_thread.scss
+++ b/lms/static/sass/discussion/views/_thread.scss
@@ -142,6 +142,7 @@
     @include clearfix();
 
     .post-header-content {
+        max-width: calc(100% - 100px);
 
         // post title
         .post-title {