If a user slides their finger off a button active area while pressing the button, the button will never go unpressed. This is because the pushbutton library function "RectangularButtonClick" has a condition statement that requires the area where the WIDGET_MSG_PTR_UP message occurs to be in the area of the button. I would recommend removing that area test in your next release.
Change:
if(GrRectContainsPoint(&psWidget->sPosition, i32X, i32Y) &&
(pPush->ui32Style & PB_STYLE_RELEASE_NOTIFY) && pPush->pfnOnClick)
To simply:
if((pPush->ui32Style & PB_STYLE_RELEASE_NOTIFY) && pPush->pfnOnClick)
gjk