ios - drawing over a view shades the view? -

i creating custom view display month , date, , looks like:

however, want add small triangle point down beneath blue month label on top. added following code in drawrect

- (void)drawrect:(cgrect)rect {     [super drawrect:rect];     cgcontextref context = uigraphicsgetcurrentcontext();     cgcontextbeginpath(context);     cgcontextmovetopoint(context, 30 - 5.0, 20);     cgcontextaddlinetopoint(context, 30 + 5.0, 20);     cgcontextaddlinetopoint(context, 30, 20 + 4.0);     cgcontextaddlinetopoint(context, 30 - 5.0, 20);     cgcontextsetrgbfillcolor(context, 0, 118/255.0, 166/255.0, 1.0);     cgcontextfillpath(context); } 

this drawing on white date label add small triangle custom view, , work. has unexpected side effect of shading date label itself. effect following:

also if zoom in image can see round corners filled in black color. looks layer properties messed maybe? happening?

thank much!