message: Demo: Added display for IsMouseDragging() function.
diff: @@ -1810,6 +1810,8 @@ void ImGui::ShowTestWindow(bool* p_open)
  if (ImGui::TreeNode("Dragging"))
  {
  ImGui::TextWrapped("You can use ImGui::GetMouseDragDelta(0) to query for the dragged amount on any widget.");
  + for (int button = 0; button < 3; button++)
  + ImGui::Text("IsMouseDragging(%d) = %d", button, ImGui::IsMouseDragging(button));
  ImGui::Button("Drag Me");
  if (ImGui::IsItemActive())
  {
  