mouse left button down

[Medium]

Please specify:
1) What is x, where does it come from, and what does it mean?
2) Who must receive the mouse event? Your application? Some other one? The whole system? As a Windows Message directly, or via SendInput?
3) Who would you like to create the event? Your application? Windows? Some other program?
4) When should the events occur? On the mere change of x?

One line questions are never good enough. I just don't get how people assume that even remotely enough infos could be packed into a hand full of words, if it's not a widely discussed topic in public or a notorious issue. If you have specific problems, by all means, be specific!