SetMinimumHeight() problem - widget is minimizing

[never_ever]

Hi,
I have problem with setMinimumHeight function.

When I create new widget I set size policy to expanding (horizontal and vertical). I have function where I set custom size of widget by setting minimum and maximum height of widget to the same size and then minimum and maximum sizes are restored to default values.

@
void MyWidget::setActive(bool isActive)
{
...
//first part
setMaximumHeight(customHeight);
setMinimumHeight(customHeight);

QApplication::processEvents();
//second part
setMaximumHeight(2000);
setMinimumHeight(1);
QApplication::processEvents();

}
@

In first part I want to resize widget (it is my widget - inheriting QDockWidget - so I can't do this by using function resize).
I do it by setting minimum and maximum height to the same value.
In second part I restore default minimum and maximum values, because I want to have possibility to resize that widget manually.
But setting minimum height to minimum (for some reasons I should set it to 1 not to 0) causes that my widget is resizing to that height and I don't know why.