diff --git a/scss/components/_collection-tree.scss b/scss/components/_collection-tree.scss
index 317402ab93..9df99379c4 100644
--- a/scss/components/_collection-tree.scss
+++ b/scss/components/_collection-tree.scss
@@ -14,6 +14,7 @@ $icons: (
 #zotero-collections-pane {
 	min-width: $min-width-collections-pane;
 	width: $min-width-collections-pane;
+	flex-shrink: 0;
 	background: var(--material-sidepane);
 }