diff --git a/src/theme.scss b/src/theme.scss
index a85bb3097..a4ff5acb3 100644
--- a/src/theme.scss
+++ b/src/theme.scss
@@ -1838,10 +1838,14 @@ tag-input {
     .file-trees {
         display: flex;
         overflow: hidden;
+        height: 100%;
     }
 
     filetree {
         width: 100%;
+        position: relative;
+        display: flex;
+        flex-direction: column;
 
         &.two-pane {
             width: 50%;
@@ -1910,6 +1914,7 @@ tag-input {
         border: 2px solid transparent;
         position: relative;
         height: 100%;
+        flex-grow: 1;
 
         &.top-scroll-indicator {
             transition: box-shadow 200ms;