Cannot use namespace 'JSX' as a value.ts(2708)

Question

I am working on a theia glsp project using TypeScript and I'm trying to add a panel to my view,

Anyway, I try to render some JSX such as React.Fragment or JsonForms but I keep getting those tags underlined with this error:

Cannot use namespace 'JSX' as a value.ts(2708)

do you have a clue about this issue