fix box scrolling in firefox

Author: runnabro

client/assets/styles/scss/sidebar/sidebar-boxes.scss

@@ -3,6 +3,7 @@
   display: flex;
   flex: 1 1 auto;
   flex-direction: column;
+  height: calc(100% - 108px);
   position: relative;
   z-index: $z-sidebar-content;