QSlider direct jump on click
if (invertedAppearance()) {
        this-&gt;setValue( maximum() - newVal ); 
} else {
        this-&gt;setValue(newVal);
}


You should not be posting if/else statements without Curly Braces. The style leaves you open for massive bugs, and as an after thought: makes it cumbersome for you or other developers to add to this code.

So for example, let's say you are editing or debugging your code, and decide to comment out a line:

if (invertedAppearance())
    this-&gt;setValue( maximum() - newVal );
else
    // this-&gt;setValue(newVal); 

event-&gt;accept();


Do you see the issue?