Make tab navigation more intuitive

modules/corelib/ui/uimovabletabbar.lua

@@ -390,6 +390,8 @@ function UIMoveableTabBar:selectNextTab()
       local widget = showPostTab(self)
       self:selectTab(widget)
       updateTabs(self)
+    else
+      self:selectTab(self.tabs[1])
     end
     return
   end
@@ -418,6 +420,8 @@ function UIMoveableTabBar:selectPrevTab()
       local widget = showPreTab(self)
       self:selectTab(widget)
       updateTabs(self)
+    else
+      self:selectTab(self.tabs[#self.tabs])
     end
     return
   end
@@ -461,4 +465,4 @@ function UIMoveableTabBar:setNavigation(prevButton, nextButton)
     nextNavigation.onClick = function() self:selectNextTab() end
   end
   updateNavigation(self)
-end
+end