[Interest] QWidget style change and reverting it back

[Prav]

I am trying to change color of QLineEdit with

ui->lineEdit->setStyleSheet("color: red;");

How  that could be that doing the same thing second time I got changed
size of lineEdit? ... Windows, Qt 5.5.1 ... test project is inside zip-file.


And  how  to  make lineEdit look as it was before using it's setStyleSheet() method?
ui->lineEdit->setStyleSheet("");
does not work for me.

Or using setStyleSheet() is irreversible operation?
If so how to change color of widget and then return it back.