Docking: Fixed DockSpace() child window displaying a scrollbar behind the node backgrounds. Rename ImGuiCol_DockingBg to ImGuiCol_DockingEmptyBg. Added ImGuiDockNode::IsLeaftNode(). (#2109)

docs/CHANGELOG.txt

@@ -47,7 +47,7 @@ HOW TO UPDATE?
 - Added ImGuiWindowFlags_UnsavedDocument window flag to append '*' to title without altering the ID, 
   as a convenience to avoid using the ### operator. 
 - Added io.ConfigDockingWithShift option to configure docking mode.
-- Style: Added ImGuiCol_DockingPreview, ImGuiCol_DockingBg colors. (#351)
+- Style: Added ImGuiCol_DockingPreview, ImGuiCol_DockingEmptyBg colors. (#351)
 - Style: Added ImGuiCol_Tab, ImGuiCol_TabHovered, ImGuiCol_TabActive, ImGuiCol_TabUnfocused, ImGuiCol_TabUnfocusedActive colors. (#261, #351)
 - Demo: Added Layout->Tabs demo code. (#261, #351)
 - Demo: Added "Documents" example app showcasing possible use for tabs. (#261, #351)

imgui.cpp

@@ -6040,7 +6040,7 @@ const char* ImGui::GetStyleColorName(ImGuiCol idx)
     case ImGuiCol_TabUnfocused: return "TabUnfocused";
     case ImGuiCol_TabUnfocusedActive: return "TabUnfocusedActive";
     case ImGuiCol_DockingPreview: return "DockingPreview";
-    case ImGuiCol_DockingBg: return "DockingBg";
+    case ImGuiCol_DockingEmptyBg: return "DockingEmptyBg";
     case ImGuiCol_PlotLines: return "PlotLines";
     case ImGuiCol_PlotLinesHovered: return "PlotLinesHovered";
     case ImGuiCol_PlotHistogram: return "PlotHistogram";
@@ -10059,7 +10059,7 @@ void ImGui::DockContextProcessDock(ImGuiContext* ctx, ImGuiDockRequest* req)
     {
         payload_node = payload_window->DockNodeAsHost;
         payload_window->DockNodeAsHost = NULL; // Important to clear this as the node will have its life as a child which might be merged/deleted later.
-        if (payload_node && !payload_node->IsSplitNode())
+        if (payload_node && payload_node->IsLeafNode())
             next_selected_id = payload_node->TabBar->NextSelectedTabId ? payload_node->TabBar->NextSelectedTabId : payload_node->TabBar->SelectedTabId;
         if (payload_node == NULL)
             next_selected_id = payload_window->ID;
@@ -10177,7 +10177,7 @@ void ImGui::DockContextProcessUndockWindow(ImGuiContext* ctx, ImGuiWindow* windo
 void ImGui::DockContextProcessUndockNode(ImGuiContext* ctx, ImGuiDockNode* node)
 {
     (void)ctx;
-    IM_ASSERT(!node->IsSplitNode());
+    IM_ASSERT(node->IsLeafNode());
     IM_ASSERT(node->Windows.Size >= 1);
 
     // In the case of a root node or document root, the node will have to stay in place. Create a new node to receive the payload.
@@ -10545,7 +10545,7 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
     }
 
     // Early out for hidden root dock nodes (when all DockId references are in inactive windows, or there is only 1 floating window holding on the DockId)
-    if (node->IsRootNode() && !node->IsSplitNode() && node->Windows.Size <= 1 && !node->IsDockSpace)
+    if (node->IsRootNode() && node->IsLeafNode() && node->Windows.Size <= 1 && !node->IsDockSpace)
     {
         if (node->Windows.Size == 1)
         {
@@ -10649,14 +10649,11 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
             DockNodeStartMouseMovingWindow(node, node->HostWindow);
     }
 
-    // Update active node (the one whose title bar is highlight) within a node tree
+    // Update focused node (the one whose title bar is highlight) within a node tree
     if (node->IsSplitNode())
         IM_ASSERT(node->TabBar == NULL);
     if (node->IsRootNode())
     {
-        //if (!node->IsSplitNode())
-        //    node->LastFocusedNodeID = node->ID;  // This also ensure on our creation frame we will receive the title screen highlight
-        //else
         if (g.NavWindow && g.NavWindow->RootWindowDockStop->DockNode && g.NavWindow->RootWindowDockStop->ParentWindow == host_window)
             node->LastFocusedNodeID = g.NavWindow->RootWindowDockStop->DockNode->ID;
     }
@@ -10679,7 +10676,7 @@ static void ImGui::DockNodeUpdate(ImGuiDockNode* node)
     {
         // Background for empty nodes
         if (node->Windows.Size == 0 && !node->IsSplitNode())
-            host_window->DrawList->AddRectFilled(node->Pos, node->Pos + node->Size, GetColorU32(ImGuiCol_DockingBg));
+            host_window->DrawList->AddRectFilled(node->Pos, node->Pos + node->Size, GetColorU32(ImGuiCol_DockingEmptyBg));
 
         // Drop target
         if (node->IsRootNode() && (g.MovingWindow == NULL || g.MovingWindow->RootWindow != host_window))
@@ -11285,7 +11282,7 @@ void ImGui::DockNodeTreeUpdatePosSize(ImGuiDockNode* node, ImVec2 pos, ImVec2 si
 {
     node->Pos = pos;
     node->Size = size;
-    if (!node->IsSplitNode())
+    if (node->IsLeafNode())
         return;
 
     ImGuiDockNode* child_0 = node->ChildNodes[0];
@@ -11347,7 +11344,7 @@ void ImGui::DockNodeTreeUpdatePosSize(ImGuiDockNode* node, ImVec2 pos, ImVec2 si
 
 static void DockNodeTreeUpdateSplitterFindTouchingNode(ImGuiDockNode* node, ImGuiAxis axis, int side, ImVector<ImGuiDockNode*>* touching_nodes)
 {
-    if (!node->IsSplitNode())
+    if (node->IsLeafNode())
     {
         touching_nodes->push_back(node);
         return;
@@ -11362,7 +11359,7 @@ static void DockNodeTreeUpdateSplitterFindTouchingNode(ImGuiDockNode* node, ImGu
 
 void ImGui::DockNodeTreeUpdateSplitter(ImGuiDockNode* node)
 {
-    if (!node->IsSplitNode())
+    if (node->IsLeafNode())
         return;
 
     ImGuiContext& g = *GImGui;
@@ -11483,7 +11480,7 @@ ImGuiDockNode* ImGui::DockNodeTreeFindNodeByPos(ImGuiDockNode* node, ImVec2 pos)
     if (!inside)
         return NULL;
 
-    if (!node->IsSplitNode())
+    if (node->IsLeafNode())
         return node;
     if (ImGuiDockNode* hovered_node = DockNodeTreeFindNodeByPos(node->ChildNodes[0], pos))
         return hovered_node;
@@ -11562,6 +11559,7 @@ void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags doc
 
     ImGuiWindowFlags window_flags = ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_DockNodeHost;
     window_flags |= ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoTitleBar;
+    window_flags |= ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse;
 
     char title[256];
     ImFormatString(title, IM_ARRAYSIZE(title), "%s/DockSpace_%08X", window->Name, id);
@@ -11733,7 +11731,7 @@ ImGuiID ImGui::DockBuilderSplitNode(ImGuiContext* ctx, ImGuiID id, ImGuiDir spli
         return 0;
     }
 
-    IM_ASSERT(!node->IsSplitNode());    // Already Split
+    IM_ASSERT(!node->IsSplitNode()); // Assert if already Split
 
     ImGuiDockRequest req;
     req.Type = ImGuiDockRequestType_Split;
@@ -11981,7 +11979,7 @@ void ImGui::BeginDocked(ImGuiWindow* window, bool* p_open)
     }
 
     IM_ASSERT(dock_node->HostWindow);
-    IM_ASSERT(!dock_node->IsSplitNode());
+    IM_ASSERT(dock_node->IsLeafNode());
 
     // Position window
     SetNextWindowPos(dock_node->Pos);

imgui.h

@@ -1015,7 +1015,7 @@ enum ImGuiCol_
     ImGuiCol_TabUnfocused,
     ImGuiCol_TabUnfocusedActive,
     ImGuiCol_DockingPreview,
-    ImGuiCol_DockingBg,             // Empty node
+    ImGuiCol_DockingEmptyBg,        // Background color for empty node (e.g. DocRoot node with no window docked into it)
     ImGuiCol_PlotLines,
     ImGuiCol_PlotLinesHovered,
     ImGuiCol_PlotHistogram,

imgui_demo.cpp

@@ -3765,10 +3765,8 @@ void ShowExampleAppDockSpace(bool* p_open)
     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
     {

imgui_draw.cpp

@@ -211,7 +211,7 @@ void ImGui::StyleColorsDark(ImGuiStyle* dst)
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
     colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_HeaderActive] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
-    colors[ImGuiCol_DockingBg]              = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
     colors[ImGuiCol_PlotLines]              = ImVec4(0.61f, 0.61f, 0.61f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(1.00f, 0.43f, 0.35f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
@@ -268,7 +268,7 @@ void ImGui::StyleColorsClassic(ImGuiStyle* dst)
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
     colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
-    colors[ImGuiCol_DockingBg]              = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
     colors[ImGuiCol_PlotLines]              = ImVec4(1.00f, 1.00f, 1.00f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);
@@ -326,7 +326,7 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
     colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
-    colors[ImGuiCol_DockingBg]              = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
+    colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);;
     colors[ImGuiCol_PlotLines]              = ImVec4(0.39f, 0.39f, 0.39f, 1.00f);
     colors[ImGuiCol_PlotLinesHovered]       = ImVec4(1.00f, 0.43f, 0.35f, 1.00f);
     colors[ImGuiCol_PlotHistogram]          = ImVec4(0.90f, 0.70f, 0.00f, 1.00f);

imgui_internal.h

@@ -778,6 +778,7 @@ struct ImGuiDockNode
     ~ImGuiDockNode();
     bool                    IsRootNode() const  { return ParentNode == NULL; }
     bool                    IsSplitNode() const { return ChildNodes[0] != NULL; }
+    bool                    IsLeafNode() const  { return ChildNodes[0] == NULL; }
     bool                    IsEmpty() const     { return ChildNodes[0] == NULL && Windows.Size == 0; }
     ImRect                  Rect() const        { return ImRect(Pos.x, Pos.y, Pos.x + Size.x, Pos.y + Size.y); }
 };