C / C++ / MFC

CClientDC dc(this);                                 
	
//Previous X, Y coordinate pair             
static int lastX=point.x, lastY=point.y;          

//Draw the tracker
dc.DrawFocusRect(CRect(-10, -10, lastX, lastY));     //Draw at previous pos to remove  
dc.DrawFocusRect(CRect(-10, -10, point.x, point.y)); //Draw at current pos to display    
	
//Assign new location to previous location  
lastX = point.x;  
lastY = point.y; 

static BOOL bFirst = TRUE;

//Previous X, Y coordinate pair             
static int lastX=point.x, lastY=point.y;           

//Draw the tracker
if(bFirst)
    dc.DrawFocusRect(CRect(-10, -10, point.x, point.y)); //Draw current 
else{
    dc.DrawFocusRect(CRect(-10, -10, lastX, lastY));     //Draw previous, removes last
    dc.DrawFocusRect(CRect(-10, -10, point.x, point.y)); //Draw current, redraws
}
	
//Assign new location to previous location  
lastX = point.x;  
lastY = point.y;

//Drawing code has made one pass
bFirst = FALSE;

abc.Create("Hello",WS_VISIBLE|WS_CHILD,CRect(10,10,100,100),
    this,10000);