diff --git a/src/styles/App.less b/src/styles/App.less
index 89df32a..8f7e2cc 100644
--- a/src/styles/App.less
+++ b/src/styles/App.less
@@ -160,6 +160,7 @@ tr.table_row_size {
 }
 
 .header-tree-select{
+  width: 300px;
   border: 1px solid rgba(255, 255, 255, 0.2);
   background-color: rgba(0, 0, 0, 0.3);
 }