Tableview with grabGesture but it's slider should work with non-grabGesture logic

[omnio2006]

My goal is to have a Tableview that has 2 specific things:

Thing #1:

1.1 Left mouse button UP behaviour:
When I press with the left mouse button and hold it on the view with rows and columns and move the mouse UP
=> I want to see the "QScroller::grabGesture" behaviour, it means that - the table moves down,
and the slider on the scrollbar also moves down, while the mouse coursor with the pressed left button moves UP.

1.2 Left mouse button DOWN behaviour:
When I press with the left mouse button and hold it on the view with rows and columns and move the mouse DOWN
=> I want to see the "QScroller::grabGesture" behaviour, it means that - the table moves up,
and the slider on the scrollbar also moves up, while the mouse coursor with the pressed left button moves DOWN.

Thing #2:

When I press with the left mouse button and hold it on the SLIDER and move the mouse up or down
=> I want to turn the "QScroller::grabGesture" behaviour OFF, and use the slider in his "default" mode, - if I move the slider down then the table moves down and if I move the slider up then the table moves up.

------------------------
In my sample project QtWgtScrollerTestApp I achieve that. But I came across some problems:

#1 Problem:
I need to wait some time (around 200 or 400 milliseconds) after I press on the Slider for the signal QScrollBar::sliderPressed to be emited.
If I start to move the mouse at the same time when I press on the slider, sliderMoved signal emits earlier and sliderPressed seems not to be emited at all after that.

#2 Problem:
When I start my app, and right away CLICK (press and release) with the left mouse button on the slider I am getting a "Segmentation fault" somewhere in a qmap source code

const QMapNodeBase *QMapNodeBase::nextNode() const
{
    const QMapNodeBase *n = this;
    if (n->right) {
        n = n->right;
        while (n->left) // <- "Segmentation fault" line
            n = n->left;
    } else {

const QMapNodeBase *QMapNodeBase::nextNode() const
{
    const QMapNodeBase *n = this;
    if (n->right) {
        n = n->right;
        while (n->left) // <- "Segmentation fault" line
            n = n->left;
    } else {

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QUESTION:
What is the correct way to achieve the behavior for a tableview and the slider that I want and have discribed above (with Thing #1 + Thing #2) ?
If my sample project is generally correct, how do I get ridd of the 2 problems described above ?
Or at least how to avoid the "Segmentation fault" problem in my project ?