diff --git a/browse/css/tree.css b/browse/css/tree.css
index ca5726d..ff2a29d 100644
--- a/browse/css/tree.css
+++ b/browse/css/tree.css
@@ -244,6 +244,11 @@ body {
 
 .preview-pane__body {
     flex: 1;
+    min-height: 0;          /* critical: lets the flex child shrink to fit
+                               the viewport instead of growing to its
+                               content's natural size (which clips the
+                               YAML editor's bottom when there are many
+                               lines, even with the editor's own scroll) */
     overflow: auto;
     display: flex;
     flex-direction: column;