Docking: Untangle a little bit of the ActiveIdClickOffset mess.

imgui.cpp

@@ -3414,7 +3414,7 @@ void ImGui::StartMouseMovingWindow(ImGuiWindow* window)
     SetActiveID(window->MoveId, window);
     g.NavDisableHighlight = true;
     g.ActiveIdNoClearOnFocusLoss = true;
-    g.ActiveIdClickOffset = g.IO.MousePos - window->RootWindow->Pos;
+    g.ActiveIdClickOffset = g.IO.MouseClickedPos[0] - window->RootWindow->Pos;
 
     bool can_move_window = true;
     if ((window->Flags & ImGuiWindowFlags_NoMove) || (window->RootWindow->Flags & ImGuiWindowFlags_NoMove))
@@ -3447,15 +3447,9 @@ void ImGui::StartMouseMovingWindowOrNode(ImGuiWindow* window, ImGuiDockNode* nod
     const bool clicked = IsMouseClicked(0);
     const bool dragging = IsMouseDragging(0, g.IO.MouseDragThreshold * 1.70f);
     if (can_undock_node && dragging)
-    {
-        DockContextQueueUndockNode(&g, node);
-        g.ActiveIdClickOffset = g.IO.MouseClickedPos[0] - node->Pos;
-    }
+        DockContextQueueUndockNode(&g, node); // Will lead to DockNodeStartMouseMovingWindow() -> StartMouseMovingWindow() being called next frame
     else if (!can_undock_node && (clicked || dragging) && g.MovingWindow != window)
-    {
         StartMouseMovingWindow(window);
-        g.ActiveIdClickOffset = g.IO.MouseClickedPos[0] - window->RootWindow->Pos;
-    }
 }
 
 // Handle mouse moving window
@@ -12775,11 +12769,10 @@ static void ImGui::DockNodeStartMouseMovingWindow(ImGuiDockNode* node, ImGuiWind
 {
     ImGuiContext& g = *GImGui;
     IM_ASSERT(node->WantMouseMove == true);
-    ImVec2 backup_active_click_offset = g.ActiveIdClickOffset;
     StartMouseMovingWindow(window);
+    g.ActiveIdClickOffset = g.IO.MouseClickedPos[0] - node->Pos;
     g.MovingWindow = window; // If we are docked into a non moveable root window, StartMouseMovingWindow() won't set g.MovingWindow. Override that decision.
     node->WantMouseMove = false;
-    g.ActiveIdClickOffset = backup_active_click_offset;
 }
 
 // Update CentralNode, OnlyNodeWithWindows, LastFocusedNodeID. Copy window class.
@@ -13296,7 +13289,7 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
             window->DockTabItemRect = host_window->DC.LastItemRect;
 
             // Update navigation ID on menu layer
-            if (g.NavWindow && g.NavWindow->RootWindowDockStop == window && (window->DC.NavLayerActiveMask & (1 << 1)) == 0)
+            if (g.NavWindow && g.NavWindow->RootWindowDockStop == window && (window->DC.NavLayerActiveMask & (1 << ImGuiNavLayer_Menu)) == 0)
                 host_window->NavLastIds[1] = window->ID;
         }
     }