Docking: mark window payload as not cross-context.

imgui.cpp

@@ -4455,7 +4455,7 @@ ImGuiIO& ImGui::GetIO()
 
 ImGuiPlatformIO& ImGui::GetPlatformIO()
 {
-    IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() or ImGui::SetCurrentContext()?");
+    IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() and ImGui::SetCurrentContext()?");
     return GImGui->PlatformIO;
 }
 
@@ -19464,7 +19464,8 @@ void ImGui::BeginDockableDragDropSource(ImGuiWindow* window)
     window = window->RootWindowDockTree;
     IM_ASSERT((window->Flags & ImGuiWindowFlags_NoDocking) == 0);
     bool is_drag_docking = (g.IO.ConfigDockingWithShift) || ImRect(0, 0, window->SizeFull.x, GetFrameHeight()).Contains(g.ActiveIdClickOffset); // FIXME-DOCKING: Need to make this stateful and explicit
-    if (is_drag_docking && BeginDragDropSource(ImGuiDragDropFlags_SourceNoPreviewTooltip | ImGuiDragDropFlags_SourceNoHoldToOpenOthers | ImGuiDragDropFlags_SourceAutoExpirePayload))
+    ImGuiDragDropFlags drag_drop_flags = ImGuiDragDropFlags_SourceNoPreviewTooltip | ImGuiDragDropFlags_SourceNoHoldToOpenOthers | ImGuiDragDropFlags_PayloadAutoExpire | ImGuiDragDropFlags_PayloadNoCrossContext | ImGuiDragDropFlags_PayloadNoCrossProcess;
+    if (is_drag_docking && BeginDragDropSource(drag_drop_flags))
     {
         SetDragDropPayload(IMGUI_PAYLOAD_TYPE_WINDOW, &window, sizeof(window));
         EndDragDropSource();