When switching from one state to another in the qmldesigner then the tr checkbox is not shown as toggled correctly. If some text is marked as translatable and you switch to another state then it will be toggled fine. But switching back again will untoggle the box making it seem it is not translatable anymore.

With the attached example, click on the text element and then switch to State2 and then back to the main state.

I couldn't test this in Qt Creator 3.0 as the button was not visible there so I don't know if it is already fixed or not.