CMake Error under ubuntu

[zhangfq-chemistry]

CMake Error at Externals/magnum-integration/modules/FindImGui.cmake:81 (get_target_property):
get_target_property() called with non-existent target "imgui::imgui".
Call Stack (most recent call first):
Externals/magnum-integration/src/Magnum/ImGuiIntegration/CMakeLists.txt:30 (find_package)

I have checked Externals and everything is there, including: corrade, glfw, imgui, ImGuizmo, magnum, and magnum-integration