Hi Zhengting,
You can activate the Design tab in the “About Plugins” settings in the Qt Creator menu. Just search for “Design” in About Plugins, where you can see that “QmlDesigner” is not active. You can activate it and restart Qt Creator to enable the “Design” tab.
However, in general we do not recommend using the Designer for Felgo projects, as its functionality is very limited. It does not handle complex files well, and only some of the Felgo components are supported.
Instead, you can use Felgo’s QML Hot Reload to develop your QML UI with a live preview.
