Docking: Internals: added ImGuiDockNodeFlags_NoUndocking. (#2999, #6823, #6780)

imgui.cpp

@@ -4461,7 +4461,7 @@ void ImGui::StartMouseMovingWindowOrNode(ImGuiWindow* window, ImGuiDockNode* nod
 {
     ImGuiContext& g = *GImGui;
     bool can_undock_node = false;
-    if (node != NULL && node->VisibleWindow && (node->VisibleWindow->Flags & ImGuiWindowFlags_NoMove) == 0)
+    if (node != NULL && node->VisibleWindow && (node->VisibleWindow->Flags & ImGuiWindowFlags_NoMove) == 0 && (node->MergedFlags & ImGuiDockNodeFlags_NoUndocking) == 0)
     {
         // Can undock if:
         // - part of a floating node hierarchy with more than one visible node (if only one is visible, we'll just move the whole hierarchy)
@@ -19893,6 +19893,7 @@ static void DebugNodeDockNodeFlags(ImGuiDockNodeFlags* p_flags, const char* labe
     CheckboxFlags("NoDockingOverMe", p_flags, ImGuiDockNodeFlags_NoDockingOverMe);
     CheckboxFlags("NoDockingOverOther", p_flags, ImGuiDockNodeFlags_NoDockingOverOther);
     CheckboxFlags("NoDockingOverEmpty", p_flags, ImGuiDockNodeFlags_NoDockingOverEmpty);
+    CheckboxFlags("NoUndocking", p_flags, ImGuiDockNodeFlags_NoUndocking);
     if (!enabled)
         EndDisabled();
     PopStyleVar();

imgui_internal.h

@@ -1679,8 +1679,9 @@ enum ImGuiDockNodeFlagsPrivate_
     ImGuiDockNodeFlags_NoDockingOverMe          = 1 << 19,  //       // [EXPERIMENTAL] Prevent another window/node to be docked over this node.
     ImGuiDockNodeFlags_NoDockingOverOther       = 1 << 20,  //       // [EXPERIMENTAL] Prevent this node to be docked over another window or non-empty node.
     ImGuiDockNodeFlags_NoDockingOverEmpty       = 1 << 21,  //       // [EXPERIMENTAL] Prevent this node to be docked over an empty node (e.g. DockSpace with no other windows)
-    ImGuiDockNodeFlags_NoResizeX                = 1 << 22,  //       // [EXPERIMENTAL]
-    ImGuiDockNodeFlags_NoResizeY                = 1 << 23,  //       // [EXPERIMENTAL]
+    ImGuiDockNodeFlags_NoUndocking              = 1 << 22,  //       // Disable undocking from this node.
+    ImGuiDockNodeFlags_NoResizeX                = 1 << 23,  //       // [EXPERIMENTAL]
+    ImGuiDockNodeFlags_NoResizeY                = 1 << 24,  //       // [EXPERIMENTAL]
     ImGuiDockNodeFlags_SharedFlagsInheritMask_  = ~0,
     ImGuiDockNodeFlags_NoResizeFlagsMask_       = ImGuiDockNodeFlags_NoResize | ImGuiDockNodeFlags_NoResizeX | ImGuiDockNodeFlags_NoResizeY,
     // When splitting those flags are moved to the inheriting child, never duplicated

imgui_widgets.cpp

@@ -8639,7 +8639,8 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
         }
 
         // Extract a Dockable window out of it's tab bar
-        if (docked_window != NULL && !(docked_window->Flags & ImGuiWindowFlags_NoMove))
+        const bool can_undock = docked_window != NULL && !(docked_window->Flags & ImGuiWindowFlags_NoMove) && !(node->MergedFlags & ImGuiDockNodeFlags_NoUndocking);
+        if (can_undock)
         {
             // We use a variable threshold to distinguish dragging tabs within a tab bar and extracting them out of the tab bar
             bool undocking_tab = (g.DragDropActive && g.DragDropPayload.SourceId == id);