[Openflipper] How to change the "Switch viewer layout" in the toolbar

Dear Openflipper, In code, we are able to call the following instruction to switch the view mode from single to double. RPC::callFunction("core", "MultiViewMode", 1); However, I found that the combo of "Switch viewer layout" in the toolbar did not change. It was still in the first item. How could I change it in code? Best Regards, Xianyong Liu.