#3504655: UI enhancement

Closes #3504655

css/pb.css

@@ -67,7 +67,8 @@
 
 .pb-filter__multi-dropdown__items--visible {
   position: absolute;
-  z-index: 100;
+  /* This needs to be underneath the loading overlay. */
+  z-index: 90;
   top: 47px;
   right: 0;
   display: block;
@@ -1113,3 +1114,19 @@
   padding: 5px;
   font-size: 0.79rem;
 }
+
+[data-project-browser-instance-id] {
+  position: relative;
+}
+
+[data-project-browser-instance-id] .pb-projects__loading-overlay {
+  position: absolute;
+  /* No element of the Project Browser UI should have a higher z-index than this. */
+  z-index: 100;
+  top: 0;
+  left: 0;
+  display: flex;
+  width: 100%;
+  height: 100%;
+  background: rgba(255, 255, 255, 0.6);
+}