Docking: Demo: Displaying a message if master docking flag is disabled. + DockSpace() early out + comments.

imgui.cpp

@@ -11475,6 +11475,8 @@ void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags doc
     ImGuiContext* ctx = GImGui;
     ImGuiContext& g = *ctx;
     ImGuiWindow* window = GetCurrentWindow();
+    if (!(g.IO.ConfigFlags & ImGuiConfigFlags_DockingEnable))
+        return;
 
     ImGuiDockNode* node = DockContextFindNodeByID(ctx, id);
     if (!node)

imgui.h

@@ -524,11 +524,12 @@ namespace ImGui
 
     // Docking 
     // [BETA API] Enable with io.ConfigFlags |= ImGuiConfigFlags_DockingEnable.
-    // Note: you DO NOT need to call DockSpace() to use most Docking facilities! You can hold SHIFT anywhere while moving windows. 
+    // Note: you DO NOT need to call DockSpace() to use most Docking facilities! 
+    // To dock windows: hold SHIFT anywhere while moving windows (if io.ConfigDockingWithKeyMod == true) or drag windows from their title bar (if io.ConfigDockingWithKeyMod = false)
     // Use DockSpace() to create an explicit dock node _within_ an existing window. See Docking demo for details.
     IMGUI_API void          DockSpace(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiDockNodeFlags flags = 0, const ImGuiDockFamily* dock_family = NULL);
     IMGUI_API void          SetNextWindowDockId(ImGuiID dock_id, ImGuiCond cond = 0);           // set next window dock id (FIXME-DOCK)
-    IMGUI_API void          SetNextWindowDockFamily(const ImGuiDockFamily* dock_family);        // FIXME-DOCK: set next window user type (docking filters by same user_type)
+    IMGUI_API void          SetNextWindowDockFamily(const ImGuiDockFamily* dock_family);        // set next window user type (docking filters by same user_type)
     IMGUI_API ImGuiID       GetWindowDockId();
     IMGUI_API bool          IsWindowDocked();                                                   // is current window docked into another window? 
 

imgui_demo.cpp

@@ -129,6 +129,16 @@ static void ShowHelpMarker(const char* desc)
     }
 }
 
+static void ShowDockingDisabledMessage()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    ImGui::Text("ERROR: Docking is not enabled! See Demo > Configuration.");
+    ImGui::Text("Set io.ConfigFlags |= ImGuiConfigFlags_DockingEnable in your code, or ");
+    ImGui::SameLine(0.0f, 0.0f);
+    if (ImGui::SmallButton("click here"))
+        io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+}
+
 // Helper to display basic user controls.
 void ImGui::ShowUserGuide()
 {
@@ -3752,10 +3762,18 @@ void ShowExampleAppDockSpace(bool* p_open)
         ImGui::EndMenuBar();
     }
 
+    ImGuiIO& io = ImGui::GetIO();
+    if (io.ConfigFlags & ImGuiConfigFlags_DockingEnable)
+    {
         //ImGui::PushStyleColor(ImGuiCol_DockingBg, ImVec4(0.2f, 0.2f, 0.2f, 1.0f));
         ImGuiID dockspace_id = ImGui::GetID("MyDockspace");
         ImGui::DockSpace(dockspace_id);
         //ImGui::PopStyleColor();
+    }
+    else
+    {
+        ShowDockingDisabledMessage();
+    }
 
     ImGui::End();
     if (opt_fullscreen)
@@ -3963,6 +3981,8 @@ void ShowExampleAppDocuments(bool* p_open)
         ImGui::EndTabBar();
     }
     else if (opt_target == Target_Window)
+    {
+        if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_DockingEnable)
         {
             NotifyOfDocumentsClosedElsewhere(app);
             
@@ -3998,6 +4018,11 @@ void ShowExampleAppDocuments(bool* p_open)
                 ImGui::End();
             }
         }
+        else
+        {
+            ShowDockingDisabledMessage();
+        }
+    }
 
     // Update closing queue
     static ImVector<MyDocument*> close_queue;