diff --git a/source/main/gui/imgui/OgreImGui.cpp b/source/main/gui/imgui/OgreImGui.cpp
index 3403ea9dac..e71542dfa7 100644
--- a/source/main/gui/imgui/OgreImGui.cpp
+++ b/source/main/gui/imgui/OgreImGui.cpp
@@ -25,6 +25,7 @@
 
 #include "OgreImGui.h"
 
+#include "AppContext.h"
 #include "ContentManager.h"
 #include "OgreImGuiOverlay.h"
 
@@ -137,19 +138,19 @@ void OgreImGui::renderQueueStarted(Ogre::uint8 queueGroupId,
         Ogre::Viewport* vp = Ogre::Root::getSingletonPtr()->getRenderSystem()->_getViewport();
         if(vp != NULL)
         {
-            if (vp->getOverlaysEnabled())
+            Ogre::SceneManager* sceneMgr = vp->getCamera()->getSceneManager();
+            if (vp->getOverlaysEnabled() && sceneMgr->_getCurrentRenderStage() != Ogre::SceneManager::IRS_RENDER_TO_TEXTURE)
             {
-                Ogre::SceneManager* sceneMgr = vp->getCamera()->getSceneManager();
-                if (sceneMgr->_getCurrentRenderStage() != Ogre::SceneManager::IRS_RENDER_TO_TEXTURE)
+                // Checking `sceneMgr->_getCurrentRenderStage() == Ogre::SceneManager::IRS_RENDER_TO_TEXTURE`)
+                // doesn't do the trick if the RTT is updated by calling `Ogre::RenderTarget::update()` by hand,
+                // which we do frequently.
+                // To compensate, we also check if the active viewport matches our screen viewport.
+                Ogre::Viewport* vp_target = App::GetAppContext()->GetViewport();
+                if (vp == vp_target)
                 {
-                    //ORIG//Ogre::OverlayManager::getSingleton()._queueOverlaysForRendering(vp->getCamera(), sceneMgr->getRenderQueue(), vp);
                     m_imgui_overlay->_findVisibleObjects(vp->getCamera(), sceneMgr->getRenderQueue(), vp);
                 }
             }
-            else
-            {
-                ImGui::EndFrame(); // Rendering won't happen - end frame manually.
-            }
         }
     }
 }