c++ - QLineEdit resize method has no effect on construction? -

i have class inherits qlineedit , in constructors call: this->resize(30, 30); , has no effect, line utterly shrunk. if call resize in other method, works fine. not in constructor. doesn't work when called right after object constructed in function it's created. there technicality i'm missing?

edit: changing size policy ignored hides widget completely

if qlineedit inside layout size of determined owner layout. if want make 30x30 should set size policy of line edit ignored or should set minimum , maximum size desired 1 (minimumsize same maximumsize).