Merge pull request #1619 from ItsNickBarry/tree-view-flex-shrink

do not allow TreeView .caret_tv element to shrink

src/app/ui/TreeView.js

@@ -21,6 +21,7 @@ var css = csjs`
   }
   .caret_tv {
     width: 10px;
+    flex-shrink: 0;
   }
   .label_tv {
     display: flex;