diff --git a/src/_h5ai/css/inc/dropbox.less b/src/_h5ai/css/inc/dropbox.less
index 187867d4..48e1cc29 100644
--- a/src/_h5ai/css/inc/dropbox.less
+++ b/src/_h5ai/css/inc/dropbox.less
@@ -2,7 +2,7 @@
 #content {
 	border: 1px dashed #fff;
 	border-radius: 8px;
-	.transition(all 0.2s ease-in-out);
+	.transition(border-color 0.2s ease-in-out);
 
 	&.hint {
 		border-color: #ddd;