Resetting StyleSheet of QSpinBox with empty string "" does not reset the font properties of the embedded QLineEdit

When resetting the stylesheet of a QSpinBox with empty string, the style does not revert back to the original style. If the string instead is an empty space (" "), the style properly gets reseted. Other controls such as QPushButton properly resets the style in the same scenario.

Steps to reproduce:

• Run attached sample
• Observe that the initial style sheets change the size of the controls visible
• Press button "Reset Stylesheets"
• EXPECTED: Both visible controls revert back to their original style
• ACTUAL: SpinBox does not change back to original style, instead keeping the initial stylesheet look