When QT uses qtooltip mouse to display text, the picture of the button will also be displayed and the prompt text style will be modified

Use QToolTip Problems encountered in ：

1、 The mouse will put QPushButton Of Background map Show it

2、 Set up QToolTip Style failed

if(preview) {// Preview on 
       ui->preview->setStyleSheet("border-image:url(:/style/preview_icon.png);");
       ui->preview->setToolTip(" Close the preview ");
} else {
       ui->preview->setStyleSheet("border-image:url(:/style/n_preview_icon.png);");
       ui->preview->setToolTip(" Open Preview ");
}

After modifying the code ： 

if(preview) {// Preview on 
       ui->preview->setStyleSheet("QPushButton{border-image:url(:/style/preview_icon.png);}"
                                  "QToolTip{background-color: #ffffff; color:#484848;}");
       ui->preview->setToolTip(" Close the preview ");
} else {
       ui->preview->setStyleSheet("QPushButton{border-image:url(:/style/n_preview_icon.png);}"
                                  "QToolTip{background-color: #ffffff; color:#484848;}");
       ui->preview->setToolTip(" Open Preview ");
}