Set min-width for tabs to fit spinner

src/app/righthand-panel.js

@@ -14,6 +14,7 @@ var css = csjs`
   .options {
       float: left;
       padding: 0.7em 0.3em;
+      min-width: 65px;
       font-size: 0.9em;
       cursor: pointer;
       background-color: transparent;