diff --git a/static/command-panel.css b/static/command-panel.css
index 8f2098259..a169d2759 100644
--- a/static/command-panel.css
+++ b/static/command-panel.css
@@ -122,6 +122,7 @@
 
 .command-panel .prompt-and-editor .editor {
   position: relative;
+  -webkit-flex: 1;
 }
 
 .command-panel .prompt-and-editor {