DragDrop: Added IsDragDropActive() helper which is useful for binding to decide how to handle mouse inputs.

imgui.cpp

@@ -11478,6 +11478,12 @@ void ImGui::EndDragDropTarget()
     IM_ASSERT(g.DragDropActive);
 }
 
+bool ImGui::IsDragDropActive()
+{
+    ImGuiContext& g = *GImGui;
+    return g.DragDropActive;
+}
+
 //-----------------------------------------------------------------------------
 // PLATFORM DEPENDENT HELPERS
 //-----------------------------------------------------------------------------