diff --git a/OHIFViewer/client/components/flexboxLayout/flexboxLayout.styl b/OHIFViewer/client/components/flexboxLayout/flexboxLayout.styl
index 8dc455677..03b0961a6 100644
--- a/OHIFViewer/client/components/flexboxLayout/flexboxLayout.styl
+++ b/OHIFViewer/client/components/flexboxLayout/flexboxLayout.styl
@@ -7,7 +7,7 @@ $lesionsSidebarMenuWidth = 450px
   flex: 1
   flex-flow: row nowrap
   align-items: stretch
-  height: calc(100% - $toolbarHeight);
+  height: 'calc(100% - %s)' % $toolbarHeight
   width: 100%
 
   .sidebarMenu