extensions status indicator in title bar

data/layout.xml

@@ -1061,6 +1061,9 @@ Here's a list of what's available in this release.
             <icon icon="cancel" width="20"/>
           </button-custom>
           <text id="version" text="PanoPainter" font-face="arial" font-size="11" margin="0 10 0 0" color=".2 .5 1 1"/>
+          <border id="ext-fbf" height="20" width="30" color="0 0 0 1" align="center" justify="center" margin="0 5 0 0">
+            <text id="txt-rec" text="FbF" font-face="arial" font-size="11" color="0 0 0 1"/>
+          </border>
         </node>
       </border>
       <!-- toolbar -->

src/app_layout.cpp

@@ -815,6 +815,11 @@ void App::initLayout()
             version_label->set_text(g_version);
         }
 
+        if (auto x = layout[main_id]->find<NodeBorder>("ext-fbf"))
+        {
+            x->m_color = ShaderManager::ext_framebuffer_fetch ? glm::vec4(0, 1, 0, 1) : glm::vec4(1, 0, 0, 1);
+        }
+
         brush_update();
         
         TextureManager::load("data/paper.jpg");