Added DockSpaceOverViewport() call, not sure about this because of the menu bar limitation. (#2109)

imgui.cpp

@@ -11711,6 +11711,41 @@ void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags doc
     End();
 }
 
+// Tips: Use with ImGuiDockNodeFlags_PassthruDockspace!
+// The limitation with this call is that your window won't have a menu bar. 
+// Even though we could pass window flags, it would also require the user to be able to call BeginMenuBar() somehow meaning we can't Begin/End in a single function.
+// So if you want a menu bar you need to repeat this code manually ourselves. As with advanced other Docking API, we may change this function signature.
+ImGuiID ImGui::DockSpaceOverViewport(ImGuiViewport* viewport, ImGuiDockNodeFlags dockspace_flags, const ImGuiDockFamily* dock_family)
+{
+    if (viewport == NULL)
+        viewport = GetMainViewport();
+
+    SetNextWindowPos(viewport->Pos);
+    SetNextWindowSize(viewport->Size);
+    SetNextWindowViewport(viewport->ID);
+
+    ImGuiWindowFlags host_window_flags = 0;
+    host_window_flags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoDocking;
+    host_window_flags |= ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoNavFocus;
+    if (dockspace_flags & ImGuiDockNodeFlags_PassthruDockspace)
+        host_window_flags |= ImGuiWindowFlags_NoBackground;
+
+    char label[32];
+    ImFormatString(label, IM_ARRAYSIZE(label), "DockspaceViewport_%08X", viewport->ID);
+
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
+    ImGui::Begin(label, NULL, host_window_flags);
+    ImGui::PopStyleVar(3);
+
+    ImGuiID dockspace_id = ImGui::GetID("Dockspace");
+    ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags, dock_family);
+    ImGui::End();
+
+    return dockspace_id;
+}
+
 //-----------------------------------------------------------------------------
 // Docking: Builder Functions
 //-----------------------------------------------------------------------------

imgui.h

@@ -528,6 +528,7 @@ namespace ImGui
     // To dock windows: hold SHIFT anywhere while moving windows (if io.ConfigDockingWithShift == true) or drag windows from their title bar (if io.ConfigDockingWithShift = 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 ImGuiID       DockSpaceOverViewport(ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags dockspace_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);        // set next window user type (docking filters by same user_type)
     IMGUI_API ImGuiID       GetWindowDockId();

imgui_demo.cpp

@@ -3768,7 +3768,7 @@ void ShowExampleAppDockSpace(bool* p_open)
 
     // When using ImGuiDockNodeFlags_PassthruDockspace, DockSpace() will render our background and handle the pass-thru hole, so we ask Begin() to not render a background.
     if (opt_flags & ImGuiDockNodeFlags_PassthruDockspace)
-        ImGui::SetNextWindowBgAlpha(0.0f);
+        window_flags |= ImGuiWindowFlags_NoBackground;
 
     ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
     ImGui::Begin("DockSpace Demo", p_open, window_flags);