diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 8fb2166..d4b0ea7 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -38,7 +38,7 @@
     Set with `io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;`.
   - Added DockSpace() API.
   - Added ImGuiDockNodeFlags flags for DockSpace().
-  - Added SetNextWindowDock(), SetNextWindowDockFamily() API.
+  - Added SetNextWindowDock(), SetNextWindowClass() API.
   - Added GetWindowDockId(), IsWindowDocked() API.
   - Added ImGuiWindowFlags_NoDocking window flag to disable the possibility for a window to be docked.
     Popup, Menu and Child windows always have the ImGuiWindowFlags_NoDocking flag set.
diff --git a/docs/TODO.txt b/docs/TODO.txt
index 3594d88..4fd3fad 100644
--- a/docs/TODO.txt
+++ b/docs/TODO.txt
@@ -145,7 +145,7 @@
  - dock: B- tab bar: make selected tab always shows its full title?
  - dock: B- tab bar: the order/focus restoring code could be part of TabBar and not DockNode? (#8)
  - dock: B- nav: design interactions so nav controls can dock/undock
- - dock: B- dockspace: flag to lock the dock tree and/or sizes (ImGuiDockFlags_Locked?)
+ - dock: B- dockspace: flag to lock the dock tree and/or sizes (ImGuiDockNodeFlags_Locked?)
  - dock: B- reintroduce collapsing a floating dock node. also collapsing a docked dock node!
  - dock: B- allow dragging a non-floating dock node by clicking on the title-bar-looking section (not just the collapse/menu button)
  - dock: B- option to remember undocked window size? (instead of keeping their docked size) (relate to #2104)
diff --git a/imgui.cpp b/imgui.cpp
index 4f2ff59..aaa07d0 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -5084,7 +5084,7 @@
     {
         window->SizeContentsExplicit = ImVec2(0.0f, 0.0f);
     }
-    window->DockFamily = g.NextWindowData.DockFamily;
+    window->WindowClass = g.NextWindowData.WindowClass;
     if (g.NextWindowData.CollapsedCond)
         SetWindowCollapsed(window, g.NextWindowData.CollapsedVal, g.NextWindowData.CollapsedCond);
     if (g.NextWindowData.FocusCond)
@@ -6531,10 +6531,10 @@
     g.NextWindowData.DockId = id;
 }
 
-void ImGui::SetNextWindowDockFamily(const ImGuiDockFamily* family)
+void ImGui::SetNextWindowClass(const ImGuiWindowClass* window_class)
 {
     ImGuiContext& g = *GImGui;
-    g.NextWindowData.DockFamily = *family;
+    g.NextWindowData.WindowClass = *window_class;
 }
 
 // In window space (not screen space!)
@@ -10679,7 +10679,7 @@
     ImGuiDockNode*      CentralNode;
     ImGuiDockNode*      FirstNodeWithWindows;
     int                 CountNodesWithWindows;
-    //ImGuiDockFamily   DockFamilyForMerges;
+    //ImGuiWindowClass  WindowClassForMerges;
 
     ImGuiDockNodeUpdateScanResults() { CentralNode = FirstNodeWithWindows = NULL; CountNodesWithWindows = 0; }
 };
@@ -10802,16 +10802,16 @@
         if (node->LastFocusedNodeID == 0 && results.FirstNodeWithWindows != NULL)
             node->LastFocusedNodeID = results.FirstNodeWithWindows->ID;
 
-        // Copy the dock family from of our window so it can be used for proper dock filtering.
-        // When node has mixed windows, prioritize the family with the most constraint (CompatibleWithNeutral = false) as the reference to copy.
+        // Copy the window class from of our first window so it can be used for proper dock filtering.
+        // When node has mixed windows, prioritize the class with the most constraint (CompatibleWithClassZero = false) as the reference to copy.
         // FIXME-DOCK: We don't recurse properly, this code could be reworked to work from DockNodeUpdateScanRec.
         if (ImGuiDockNode* first_node_with_windows = results.FirstNodeWithWindows)
         {
-            node->DockFamily = first_node_with_windows->Windows[0]->DockFamily;
+            node->WindowClass = first_node_with_windows->Windows[0]->WindowClass;
             for (int n = 1; n < first_node_with_windows->Windows.Size; n++)
-                if (first_node_with_windows->Windows[n]->DockFamily.CompatibleWithFamilyZero == false)
+                if (first_node_with_windows->Windows[n]->WindowClass.DockingAllowUnclassed == false)
                 {
-                    node->DockFamily = first_node_with_windows->Windows[n]->DockFamily;
+                    node->WindowClass = first_node_with_windows->Windows[n]->WindowClass;
                     break;
                 }
         }
@@ -11272,13 +11272,13 @@
     if ((host_window->Flags & ImGuiWindowFlags_DockNodeHost) && host_window->DockNodeAsHost->IsDockSpace && payload->BeginOrderWithinContext < host_window->BeginOrderWithinContext)
         return false;
 
-    ImGuiDockFamily* host_family = host_window->DockNodeAsHost ? &host_window->DockNodeAsHost->DockFamily : &host_window->DockFamily;
-    ImGuiDockFamily* payload_family = &payload->DockFamily;
-    if (host_family->FamilyId != payload_family->FamilyId)
+    ImGuiWindowClass* host_class = host_window->DockNodeAsHost ? &host_window->DockNodeAsHost->WindowClass : &host_window->WindowClass;
+    ImGuiWindowClass* payload_class = &payload->WindowClass;
+    if (host_class->ClassId != payload_class->ClassId)
     {
-        if (host_family->FamilyId != 0 && host_family->CompatibleWithFamilyZero && payload_family->FamilyId == 0)
+        if (host_class->ClassId != 0 && host_class->DockingAllowUnclassed && payload_class->ClassId == 0)
             return true;
-        if (payload_family->FamilyId != 0 && payload_family->CompatibleWithFamilyZero && host_family->FamilyId == 0)
+        if (payload_class->ClassId != 0 && payload_class->DockingAllowUnclassed && host_class->ClassId == 0)
             return true;
         return false;
     }
@@ -11928,7 +11928,7 @@
 
 // Create an explicit dockspace node within an existing window. Also expose dock node flags and creates a CentralNode by default.
 // The Central Node is always displayed even when empty and shrink/extend according to the requested size of its neighbors.
-void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags dockspace_flags, const ImGuiDockFamily* dock_family)
+void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags dockspace_flags, const ImGuiWindowClass* window_class)
 {
     ImGuiContext* ctx = GImGui;
     ImGuiContext& g = *ctx;
@@ -11943,7 +11943,7 @@
         node->IsCentralNode = true;
     }
     node->Flags = dockspace_flags;
-    node->DockFamily = dock_family ? *dock_family : ImGuiDockFamily();
+    node->WindowClass = window_class ? *window_class : ImGuiWindowClass();
 
     // When a Dockspace transitioned form implicit to explicit this may be called a second time
     // It is possible that the node has already been claimed by a docked window which appeared before the DockSpace() node, so we overwrite IsDockSpace again.
@@ -12006,7 +12006,7 @@
 // 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)
+ImGuiID ImGui::DockSpaceOverViewport(ImGuiViewport* viewport, ImGuiDockNodeFlags dockspace_flags, const ImGuiWindowClass* window_class)
 {
     if (viewport == NULL)
         viewport = GetMainViewport();
@@ -12031,7 +12031,7 @@
     PopStyleVar(3);
 
     ImGuiID dockspace_id = GetID("Dockspace");
-    DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags, dock_family);
+    DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags, window_class);
     End();
 
     return dockspace_id;
@@ -12299,7 +12299,7 @@
     IM_ASSERT((in_window_remap_pairs->Size % 2) == 0);
 
     // Duplicate entire dock
-    // FIXME: When overwriting dst_dockspace_id, windows that aren't part of our dockspace family but that are docked in a same node will be split apart,
+    // FIXME: When overwriting dst_dockspace_id, windows that aren't part of our dockspace window class but that are docked in a same node will be split apart,
     // whereas we could attempt to at least keep them together in a new, same floating node.
     ImVector<ImGuiID> node_remap_pairs;
     DockBuilderCopyNode(src_dockspace_id, dst_dockspace_id, &node_remap_pairs);
@@ -13126,7 +13126,7 @@
     else if (sscanf(line, "Collapsed=%d", &i) == 1)             { settings->Collapsed = (i != 0); }
     else if (sscanf(line, "DockId=0x%X,%d", &u1, &i) == 2)      { settings->DockId = u1; settings->DockOrder = (short)i; }
     else if (sscanf(line, "DockId=0x%X", &u1) == 1)             { settings->DockId = u1; settings->DockOrder = -1; }
-    else if (sscanf(line, "DockFamilyId=0x%X", &u1) == 1)       { settings->DockFamilyId = u1; }
+    else if (sscanf(line, "ClassId=0x%X", &u1) == 1)            { settings->ClassId = u1; }
 }
 
 static void SettingsHandlerWindow_WriteAll(ImGuiContext* imgui_ctx, ImGuiSettingsHandler* handler, ImGuiTextBuffer* buf)
@@ -13153,7 +13153,7 @@
         settings->ViewportPos = window->ViewportPos;
         IM_ASSERT(window->DockNode == NULL || window->DockNode->ID == window->DockId);
         settings->DockId = window->DockId;
-        settings->DockFamilyId = window->DockFamily.FamilyId;
+        settings->ClassId = window->WindowClass.ClassId;
         settings->DockOrder = window->DockOrder;
         settings->Collapsed = window->Collapsed;
     }
@@ -13184,8 +13184,8 @@
                 buf->appendf("DockId=0x%08X\n", settings->DockId);
             else
                 buf->appendf("DockId=0x%08X,%d\n", settings->DockId, settings->DockOrder);
-            if (settings->DockFamilyId != 0)
-                buf->appendf("DockFamilyId=0x%08X\n", settings->DockFamilyId);
+            if (settings->ClassId != 0)
+                buf->appendf("ClassId=0x%08X\n", settings->ClassId);
         }
         buf->appendf("\n");
     }
diff --git a/imgui.h b/imgui.h
index 9404c92..4873222 100644
--- a/imgui.h
+++ b/imgui.h
@@ -15,7 +15,7 @@
 // Flags & Enumerations
 // ImGuiStyle
 // ImGuiIO
-// Misc data structures (ImGuiInputTextCallbackData, ImGuiSizeCallbackData, ImGuiPayload, ImGuiDockFamily)
+// Misc data structures (ImGuiInputTextCallbackData, ImGuiSizeCallbackData, ImGuiPayload, ImGuiWindowClass)
 // Obsolete functions
 // Helpers (ImVector, ImGuiOnceUponAFrame, ImGuiTextFilter, ImGuiTextBuffer, ImGuiStorage, ImGuiListClipper, ImColor)
 // Draw List API (ImDrawCmd, ImDrawIdx, ImDrawVert, ImDrawChannel, ImDrawListFlags, ImDrawList, ImDrawData)
@@ -102,7 +102,7 @@
 typedef void* ImTextureID;          // User data to identify a texture (this is whatever to you want it to be! read the FAQ about ImTextureID in imgui.cpp)
 #endif
 struct ImGuiContext;                // ImGui context (opaque)
-struct ImGuiDockFamily;             // Docking family for dock filtering
+struct ImGuiWindowClass;            // Window class/family for docking filtering or high-level identifiation of windows by user
 struct ImGuiIO;                     // Main configuration and I/O between your application and ImGui
 struct ImGuiInputTextCallbackData;  // Shared state of InputText() when using custom ImGuiInputTextCallback (rare/advanced use)
 struct ImGuiListClipper;            // Helper to manually clip large list of items
@@ -578,10 +578,10 @@
     // Note: you DO NOT need to call DockSpace() to use most Docking facilities! 
     // 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          DockSpace(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
+    IMGUI_API ImGuiID       DockSpaceOverViewport(ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags dockspace_flags = 0, const ImGuiWindowClass* window_class = 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 void          SetNextWindowClass(const ImGuiWindowClass* window_class);           // set next window class / user type (docking filters by same user_type)
     IMGUI_API ImGuiID       GetWindowDockId();
     IMGUI_API bool          IsWindowDocked();                                                   // is current window docked into another window? 
 
@@ -1470,14 +1470,13 @@
     bool IsDelivery() const                 { return Delivery; }
 };
 
-// [BETA] For SetNextWindowDockFamily() and DockSpace() function
-struct ImGuiDockFamily
+// [BETA] Rarely used, very advanced uses only. Use with SetNextWindowClass() and DockSpace() functions.
+struct ImGuiWindowClass
 {
-    ImGuiID FamilyId;                   // 0 = unaffiliated
-    bool    CompatibleWithFamilyZero;   // true = can be docked/merged with an unaffiliated window
+    ImGuiID             ClassId;                // User data. 0 = Default class (unclassed)
+    bool                DockingAllowUnclassed;  // true = can be docked/merged with an unclassed window
 
-    ImGuiDockFamily()                                                           { FamilyId = 0; CompatibleWithFamilyZero = true; }
-    ImGuiDockFamily(ImGuiID family_id, bool compatible_with_family_zero = true) { FamilyId = family_id; CompatibleWithFamilyZero = compatible_with_family_zero; }
+    ImGuiWindowClass()  { ClassId = 0; DockingAllowUnclassed = true; }
 };
 
 //-----------------------------------------------------------------------------
diff --git a/imgui_demo.cpp b/imgui_demo.cpp
index 5fbae2c..317e59d 100644
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@@ -1541,7 +1541,7 @@
         if (test_window)
         {
             // FIXME-DOCK: This window cannot be docked within the ImGui Demo window, this will cause a feedback loop and get them stuck.
-            // Could we fix this through an ImGuiDockFamily feature? Or an API call to tag our parent as "don't skip items"?
+            // Could we fix this through an ImGuiWindowClass feature? Or an API call to tag our parent as "don't skip items"?
             ImGui::Begin("Title bar Hovered/Active tests", &test_window);
             if (ImGui::BeginPopupContextItem()) // <-- This is using IsItemHovered()
             {
diff --git a/imgui_internal.h b/imgui_internal.h
index 7578f84..687b53b 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -566,11 +566,11 @@
     ImVec2      ViewportPos;
     ImGuiID     ViewportId;
     ImGuiID     DockId;         // ID of last known DockNode (even if the DockNode is invisible because it has only 1 active window), or 0 if none. 
-    ImGuiID     DockFamilyId;   // ID of dock family if specified
+    ImGuiID     ClassId;        // ID of window class if specified
     short       DockOrder;      // Order of the last time the window was visible within its DockNode. This is used to reorder windows that are reappearing on the same frame. Same value between windows that were active and windows that were none are possible.
     bool        Collapsed;
 
-    ImGuiWindowSettings() { Name = NULL; ID = 0; Pos = Size = ViewportPos = ImVec2(0, 0); ViewportId = DockId = DockFamilyId = 0; DockOrder = -1; Collapsed = false; }
+    ImGuiWindowSettings() { Name = NULL; ID = 0; Pos = Size = ViewportPos = ImVec2(0, 0); ViewportId = DockId = ClassId = 0; DockOrder = -1; Collapsed = false; }
 };
 
 struct ImGuiSettingsHandler
@@ -734,7 +734,7 @@
     float                   BgAlphaVal;
     ImGuiID                 ViewportId;
     ImGuiID                 DockId;
-    ImGuiDockFamily         DockFamily;
+    ImGuiWindowClass        WindowClass;
     ImVec2                  MenuBarOffsetMinVal;                // This is not exposed publicly, so we don't clear it.
 
     ImGuiNextWindowData()
@@ -754,7 +754,7 @@
     void    Clear()
     {
         PosCond = SizeCond = ContentSizeCond = CollapsedCond = SizeConstraintCond = FocusCond = BgAlphaCond = ViewportCond = DockCond = 0;
-        DockFamily = ImGuiDockFamily();
+        WindowClass = ImGuiWindowClass();
     }
 };
 
@@ -781,7 +781,7 @@
     ImVec2                  Size;                       // Current size
     ImVec2                  SizeRef;                    // [Split node only] Last explicitly written-to size (overridden when using a splitter affecting the node), used to calculate Size.
     int                     SplitAxis;                  // [Split node only] Split axis (X or Y)
-    ImGuiDockFamily         DockFamily;
+    ImGuiWindowClass        WindowClass;
 
     ImGuiWindow*            HostWindow;
     ImGuiWindow*            VisibleWindow;
@@ -1201,6 +1201,7 @@
     char*                   Name;
     ImGuiID                 ID;                                 // == ImHash(Name)
     ImGuiWindowFlags        Flags, FlagsPreviousFrame;          // See enum ImGuiWindowFlags_
+    ImGuiWindowClass        WindowClass;                        // Advanced users only. Set with SetNextWindowClass()
     ImGuiViewportP*         Viewport;                           // Always set in Begin(), only inactive windows may have a NULL value here
     ImGuiID                 ViewportId;                         // We backup the viewport id (since the viewport may disappear or never be created if the window is inactive)
     ImVec2                  ViewportPos;                        // We backup the viewport position (since the viewport may disappear or never be created if the window is inactive)
@@ -1247,7 +1248,6 @@
     ImGuiCond               SetWindowDockAllowFlags;            // store acceptable condition flags for SetNextWindowDock() use.
     ImVec2                  SetWindowPosVal;                    // store window position when using a non-zero Pivot (position set needs to be processed when we know the window size)
     ImVec2                  SetWindowPosPivot;                  // store window pivot for positioning. ImVec2(0,0) when positioning from top-left corner; ImVec2(0.5f,0.5f) for centering; ImVec2(1,1) for bottom right.
-    ImGuiDockFamily         DockFamily;                         // set with SetNextWindowDockFamily()
 
     ImGuiWindowTempData     DC;                                 // Temporary per-window data, reset at the beginning of the frame. This used to be called ImGuiDrawContext, hence the "DC" variable name.
     ImVector<ImGuiID>       IDStack;                            // ID stack. ID are hashes seeded with the value at the top of the stack