diff --git a/src/Magnum/Implementation/DebugState.cpp b/src/Magnum/Implementation/DebugState.cpp
index 1e514ac54..f030a8689 100644
--- a/src/Magnum/Implementation/DebugState.cpp
+++ b/src/Magnum/Implementation/DebugState.cpp
@@ -31,8 +31,10 @@
 
 namespace Magnum { namespace Implementation {
 
-DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0), maxMessageLength(0), messageCallback(nullptr) {
+DebugState::DebugState(Context& context, std::vector<std::string>& extensions): maxLabelLength(0), maxLoggedMessages(0), maxMessageLength(0), messageCallback(nullptr) {
     if(context.isExtensionSupported<Extensions::GL::KHR::debug>()) {
+        extensions.push_back(Extensions::GL::KHR::debug::string());
+
         getLabelImplementation = &AbstractObject::getLabelImplementationKhr;
         labelImplementation = &AbstractObject::labelImplementationKhr;
         messageInsertImplementation = &DebugMessage::insertImplementationKhr;
@@ -40,6 +42,8 @@ DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0
 
     } else {
         if(context.isExtensionSupported<Extensions::GL::EXT::debug_label>()) {
+            extensions.push_back(Extensions::GL::EXT::debug_label::string());
+
             getLabelImplementation = &AbstractObject::getLabelImplementationExt;
             labelImplementation = &AbstractObject::labelImplementationExt;
         } else {
@@ -47,14 +51,17 @@ DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0
             labelImplementation = &AbstractObject::labelImplementationNoOp;
         }
 
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>())
+        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>()) {
+            extensions.push_back(Extensions::GL::EXT::debug_marker::string());
+
             messageInsertImplementation = &DebugMessage::insertImplementationExt;
         #ifndef MAGNUM_TARGET_GLES
-        else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>())
+        } else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>()) {
+            extensions.push_back(Extensions::GL::GREMEDY::string_marker::string());
+
             messageInsertImplementation = &DebugMessage::insertImplementationGremedy;
         #endif
-        else
-            messageInsertImplementation = &DebugMessage::insertImplementationNoOp;
+        } else messageInsertImplementation = &DebugMessage::insertImplementationNoOp;
 
         messageCallbackImplementation = &DebugMessage::callbackImplementationNoOp;
     }
diff --git a/src/Magnum/Implementation/DebugState.h b/src/Magnum/Implementation/DebugState.h
index 95955e1c2..a435e1b20 100644
--- a/src/Magnum/Implementation/DebugState.h
+++ b/src/Magnum/Implementation/DebugState.h
@@ -26,13 +26,14 @@
 */
 
 #include <string>
+#include <vector>
 
 #include "Magnum/DebugMessage.h"
 
 namespace Magnum { namespace Implementation {
 
 struct DebugState {
-    DebugState(Context& context);
+    explicit DebugState(Context& context, std::vector<std::string>& extensions);
 
     std::string(*getLabelImplementation)(GLenum, GLuint);
     void(*labelImplementation)(GLenum, GLuint, const std::string&);
diff --git a/src/Magnum/Implementation/State.cpp b/src/Magnum/Implementation/State.cpp
index 015773280..62ee567f1 100644
--- a/src/Magnum/Implementation/State.cpp
+++ b/src/Magnum/Implementation/State.cpp
@@ -25,6 +25,8 @@
 
 #include "State.h"
 
+#include <algorithm>
+
 #include "Magnum/Context.h"
 #include "Magnum/Extensions.h"
 
@@ -39,32 +41,31 @@
 
 namespace Magnum { namespace Implementation {
 
-State::State(Context& context):
-    buffer(new BufferState),
-    debug(new DebugState(context)),
-    framebuffer(new FramebufferState),
-    mesh(new MeshState),
-    renderer(new RendererState),
-    shader(new ShaderState),
-    shaderProgram(new ShaderProgramState),
-    texture(new TextureState)
-{
+State::State(Context& context) {
+    /* List of extensions used in current context. Guesstimate count to avoid
+       unnecessary reallocations. */
+    std::vector<std::string> extensions;
+    #ifndef MAGNUM_TARGET_GLES
+    extensions.reserve(32);
+    #else
+    extensions.reserve(8);
+    #endif
 
-    Debug() << "Using optional features:";
+    buffer = new BufferState;
+    debug = new DebugState(context, extensions);
+    framebuffer = new FramebufferState;
+    mesh = new MeshState;
+    renderer = new RendererState;
+    shader = new ShaderState;
+    shaderProgram = new ShaderProgramState;
+    texture = new TextureState;
 
-    if(context.isExtensionSupported<Extensions::GL::KHR::debug>())
-        Debug() << "   " << Extensions::GL::KHR::debug::string();
-    else {
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_label>())
-            Debug() << "   " << Extensions::GL::EXT::debug_label::string();
+    /* Sort the features and remove duplicates */
+    std::sort(extensions.begin(), extensions.end());
+    extensions.erase(std::unique(extensions.begin(), extensions.end()), extensions.end());
 
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>())
-            Debug() << "   " << Extensions::GL::EXT::debug_marker::string();
-        #ifndef MAGNUM_TARGET_GLES
-        else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>())
-            Debug() << "   " << Extensions::GL::GREMEDY::string_marker::string();
-        #endif
-    }
+    Debug() << "Using optional features:";
+    for(const auto& ext: extensions) Debug() << "   " << ext;
 }
 
 State::~State() {
diff --git a/src/Magnum/Implementation/State.h b/src/Magnum/Implementation/State.h
index 61f34a546..207594cd2 100644
--- a/src/Magnum/Implementation/State.h
+++ b/src/Magnum/Implementation/State.h
@@ -44,14 +44,14 @@ struct State {
 
     ~State();
 
-    BufferState* const buffer;
-    DebugState* const debug;
-    FramebufferState* const framebuffer;
-    MeshState* const mesh;
-    RendererState* const renderer;
-    ShaderState* const shader;
-    ShaderProgramState* const shaderProgram;
-    TextureState* const texture;
+    BufferState* buffer;
+    DebugState* debug;
+    FramebufferState* framebuffer;
+    MeshState* mesh;
+    RendererState* renderer;
+    ShaderState* shader;
+    ShaderProgramState* shaderProgram;
+    TextureState* texture;
 };
 
 }}