Why I don't have access to new window element in code of Qt application?

Question

I did add a new element (button) on window form via GUI designer, but in code I don't have access to it in Qt application. Qt Creator IDE show error and tell me, what no such element in UI of application, when I try to use it in code by object name. Why it happens?

Answer 1

Possible, database of application UI elements in IDE don't update yet. For deciding this problem, clear and rebuild project/solution. This almost always helps in similar cases.