Juce C++ - Window get empty when trying to move it

Question

I removed the title bar and borders from my window and now I am trying to make it move when I click and move using this code:

void mouseDrag(const MouseEvent& event) override {

    int x = event.getScreenPosition().x - event.getPosition().x;
    int y = event.getScreenPosition().y - event.getPosition().y;

    setTopLeftPosition(x, y);

}

It does move but I have 2 problems: 1) I have to click 2 times and then it starts moving and 2) when I start moving it, it gets empty (just grey color) no components inside it. How can I fix this?

[EDIT]

I get a bit closer with this code:

if (event.eventComponent == this)  {

        int x = event.getScreenPosition().x - lastMouseDownX;
        int y = event.getScreenPosition().y - lastMouseDownY;

        getParentComponent()->setTopLeftPosition(x, y);
}

Now the window moves without getting grey but the movement is flickering a lot and "jumps" positions.

Answer 1

It was actually really simple. All I had to do was to remove this line:

addMouseListener(this, true);

from the main gui component's constructor. Still, I don't know why this line made the window movement flickering. If anyone knows please comment.