Whatz the problem(MouseDown not responding properly)

Greetings every1,
I'm trying to make a custom CheckBox. So far I've been able to successfully draw the checkbox and the checkmark. The problem is, if u closely observe the CheckBox control included in the Windows environment, u will notice that whenever the user presses the mouse on the checkbox(MouseDown event), the checkbox window changes color to the checkbox color(vbButtonFace by default). In my checkbox, when i press the button, the control changes color sometimes and sometimes it does not. I dont know what the problem is and why its behaving like that. I'd like u guyz to take a look at it. Click the checkbox a couple of times. U'll see that occasionally, the check box window remains white and the checkmark appears. Plz help me. The project is included. Thanx in advance

It happens sometimes when you double click. Maybe the mousedown event doesn't have enough time to fire. Maybe if you catch the double click event it will solve the problem... Also, the ckeck in the check box is small, I don't know if that is how you want it...

It works fine when I click slowly...