Autoselect first tab when no tab is selected.

src/main/java/com/raoulvdberge/refinedstorage/gui/GuiCraftingMonitor.java

@@ -208,9 +208,13 @@ public class GuiCraftingMonitor extends GuiBase implements IResizableDisplay {
             return getTabById(currentTab.get());
         }
 
+        if (tasks.isEmpty()) {
             return null;
         }
 
+        return tasks.get(0);
+    }
+
     @Nullable
     private IGridTab getTabById(UUID id) {
         return tasks.stream().filter(t -> ((CraftingMonitorTask) t).id.equals(id)).findFirst().orElse(null);