SFML2 Mouse::isButtonPressed filling up event queue - c++

Question

First of all I'd like to say that I'm not sure if the title is appropriate but it's the only logical explanation I could find.
What I'm trying to do is move my window by clicking a sprite (sort of like simulating a titlebar).
All working fine until I let go of the mouse button the rate new mouse events are emitted is way lower and with huge 1.5~2s pauses between them.
Is it possible that sf::Mouse::isBUttonPressed is filling the queue or is it another issue?
Edit: The window class has a sf::Event object and passes it to each object's event handler.
The sprite class has an event handler of this form:
bool object::handleEvents(sf::Event& event)
{
switch(event.type)
{
case sf::Event::MouseMoved:
case sf::Event::MouseButtonPressed:
case sf::Event::MouseButtonReleased:
{
auto mouse_pos = sf::Mouse::getPosition(*this->parent);
if(this->isPointInside(mouse_pos))
{
if(event.type == sf::Event::MouseMoved)
{
this->hovering = true;
if(this->callback["onHover"])
this->callback["onHover"](this, nullptr);
return true;
}
else if(event.type == sf::Event::MouseButtonPressed)
{
this->clicked = true;
this->focused = true;
if(event.mouseButton.button == sf::Mouse::Left)
if(this->callback["onLClick"])
this->callback["onLClick"](this, ref(mouse_pos));
if(event.mouseButton.button == sf::Mouse::Right)
if(this->callback["onRClick"])
this->callback["onRClick"](this, ref(mouse_pos));
return true;
}
else if(event.type == sf::Event::MouseButtonReleased && this->clicked)
{
this->clicked = false;
if(event.mouseButton.button == sf::Mouse::Left)
if(this->callback["onLClickReleased"])
this->callback["onLClickReleased"](this, ref(mouse_pos));
if(event.mouseButton.button == sf::Mouse::Right)
if(this->callback["onRClickReleased"])
this->callback["onRClickReleased"](this, ref(mouse_pos));
return true;
}
}
else
{
if(this->hovering)
{
if(this->callback["onHoverLost"])
this->callback["onHoverLost"](this, nullptr);
this->hovering = false;
}
}
}break;
default: ;
}
return false;
}
and the code responsible for moving the window:
titlebar->callback["onLClick"] = [&](object* obj, void* data)
{
sf::Vector2i* relpos = (sf::Vector2i*)(data);
while(sf::Mouse::isButtonPressed(sf::Mouse::Left))
{
sf::Vector2i abspos = sf::Mouse::getPosition();
window.setPosition(sf::Vector2i((abspos.x - relpos->x),(abspos.y - relpos->y)));
}
titlebar->clicked = false;
};

Answer 1

The sf::Mouse class as well as sf::Keyboard and sf::Joystick aren't connected to the event system, but are completely independent, thus it's impossible that isButtonPressed would've any influence on the events.
The real problem in your code is the 'infinite' loop when the left mouse button is pressed. If the left mouse button is pressed, everything that happens in your application is, that the window gets moved around. There won't be any event dispatches (= processing) and every event that happens within that time, will get pilled in the event queue. Thus when you return to process the events, you'll have a longer queue than usual and will start dispatching with the oldest event.
So if you now move your window around for 2 seconds, you'll get a filled queue worth 2 seconds which can delay the further processing.
To solve this problem, you'll most probably have to dispatch all the events while you're moving the window.