Fixing studylist highlighting on IE11

Packages/ohif-viewerbase/client/components/viewer/gridLayout/gridLayout.styl

@@ -7,14 +7,16 @@
   padding-right: 12px
 
 .mainContent
+  theme('background-color', '$primaryBackgroundColor')
+
   &.sidebar-right-open
     #imageViewerViewports
       padding-right: 7px
-    
+
   &.sidebar-left-open:not(.sidebar-right-open)
     #imageViewerViewports
       padding-right: 13px
-  
+
   &.sidebar-left-open.sidebar-right-open
     #imageViewerViewports
-      padding-right: 8px
+      padding-right: 8px