QToolButton show()&hide() not correct

[daiheitan]

I have three QToolButtons in a HBoxLayout.The Pointers are Btn1,Btn2,Btn3.
At first,they are all hidden;

void initButtonStates(){
Btn1->hide();
Btn2->hide();
Btn3->hide();
}

void initButtonStates(){
Btn1->hide();
Btn2->hide();
Btn3->hide();
}

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And there are following functions:

void showBtnA(){
initButtonStates();
Btn1->show();
}
void showBtnB()....
void showBtnC()....

void showBtnA(){
initButtonStates();
Btn1->show();
}
void showBtnB()....
void showBtnC()....

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However,with the following code:

showBtnA();
showBtnB();
showBtnC();

showBtnA();
showBtnB();
showBtnC();

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BtnA is always there,and no BtnB&C
But When Using qDebug(),it shows that BtnA is not visible.But it's just there.
That's really strange.

p.s. each of the Buttons has a Stylesheet to give it a border-image(normal,hover,pressed,etc)

Thanks To any reply and i'm just waiting online.